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  • Scriptaculous Draggable/Droppable script not working properly when dragging into a scrolling div

    - by George
    I am using the Scriptaculous Draggable/Droppable scripts and have a problem when dragging into a scrolling div. I have the following layout (based on this question): #grid-container { left:33px; position:relative; width:300px; } #grid { width:310px; height:400px; overflow:auto; margin-bottom: 15px; } #grid-container ul { width:400px; list-style-type:none; white-space: nowrap; } #grid-container li { display:inline; list-style-type:none; padding:5px 15px 5px 15px; height:88px; text-align:center } .image-row { margin-left: 10px; } .grid-image { height:50px; margin-left:-20px; } Here is the html: <div id="grid-container"> <div id="grid"> <div id="row1" class="image-row"> <ul> <li><img id="img1" class="grid-image" src="images/img1.jpg"></li> <li><img id="img2" class="grid-image" src="images/img2.jpg"></li> <li><img id="img3" class="grid-image" src="images/img3.jpg"></li> <li><img id="img4" class="grid-image" src="images/img4.jpg"></li> </ul> </div> <div id="row2" class="image-row"> <ul> <li><img id="img5" class="grid-image" src="images/img5.jpg"></li> <li><img id="img6" class="grid-image" src="images/img6.jpg"></li> </ul> </div> </div> </div> I have another div with draggable items, while all of the img elements are droppable. This works very well for most cases, but when there are too many images for the grid and it has to scroll, I run into issues. I can still drag/drop into most items in that div, but when I scroll down and then try to drag onto an item in the bottom of the list, it drops on the row that was at the bottom before I scrolled the div. Even if I set the scroll attribute when creating the Draggable items, it will scroll the grid div, but not use the proper Droppable item. Is there any way to make the Draggable items drop onto the proper Droppable element regardless of if the containing div is scrolled or not?

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  • How to implement JQuery easing into this window scroll movement function?

    - by Mohammad
    With this code I've been able to capture the mousewheel movement and apply it to the horizontal scroll bars instead of the vertical default. $('html').bind('mousewheel', function(event, delta) { window.parent.scrollBy(-120 * delta, 0); return false; }); Is there any way that I could add this jQuery easing animation to the scroll movement? jQuery.extend( jQuery.easing, { easeInOutBack: function (x, t, b, c, d, s) { if (s == undefined) s = 1.70158; if ((t/=d/2) < 1) return c/2*(t*t*(((s*=(1.525))+1)*t - s)) + b; return c/2*((t-=2)*t*(((s*=(1.525))+1)*t + s) + 2) + b; } }); Thank you so much in advance!

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  • Setting UITableViewCell button image values during scrolling

    - by Rob
    I am having an issue where I am trying to save whether a repeat image will show selected or not (it is created as a UIButton on a UITableViewCell created in IB). The issue is that since the cell gets re-used randomly, the image gets reset or set somewhere else after you start scrolling. I've looked all over and the advice was to setup an NSMutableArray to store the button's selection state and I am doing that in an array called checkRepeatState My question is: where do I put the if-then-else statement in the code to where it will actually change the button image based on if the checkRepeatState is set to 0 or 1 for the given cell that is coming back into view? Right now, the if-then-else statement I am using has absolutely no effect on the button image when it comes into view. I'm very confused at this point. Thank you ahead of time for any insight you can give!!! My code is as follows: - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { // set up the cell static NSString *CellIdentifier = @"PlayerCell"; PlayerCell *cell = (PlayerCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (!cell) { [[NSBundle mainBundle] loadNibNamed:@"PlayerNibCells" owner:self options:nil]; cell = tmpCell; self.tmpCell = nil; NSLog(@"Creating a new cell"); } // Display dark and light background in alternate rows -- see tableView:willDisplayCell:forRowAtIndexPath:. cell.useDarkBackground = (indexPath.row % 2 == 0); // Configure the data for the cell. NSDictionary *dataItem = [soundCategories objectAtIndex:indexPath.row]; UILabel *label; label = (UILabel *)[cell viewWithTag:1]; label.text = [dataItem objectForKey:@"AnimalName"]; label = (UILabel *)[cell viewWithTag:2]; label.text = [dataItem objectForKey:@"Description"]; UIImageView *img; img = (UIImageView *)[cell viewWithTag:3]; img.image = [UIImage imageNamed:[dataItem objectForKey:@"Icon"]]; NSInteger row = indexPath.row; NSNumber *checkValue = [checkRepeatState objectAtIndex:row]; NSLog(@"checkValue is %d", [checkValue intValue]); // Reusing cell; make sure it has correct image based on checkRepeatState value UIButton *repeatbutton = (UIButton *)[cell viewWithTag:4]; if ([checkValue intValue] == 1) { NSLog(@"repeatbutton is selected"); [repeatbutton setImage:[UIImage imageNamed:@"repeatselected.png"] forState:UIControlStateSelected]; [repeatbutton setNeedsDisplay]; } else { NSLog(@"repeatbutton is NOT selected"); [repeatbutton setImage:[UIImage imageNamed:@"repeat.png"] forState:UIControlStateNormal]; [repeatbutton setNeedsDisplay]; } cell.accessoryType = UITableViewCellAccessoryNone; return cell; }

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  • liquid CSS issues - rtl, floating and scrollers

    - by Rani
    hi I want to build a site that will have these restrictions: RTL direction vertical scroll on the right side whole page is floating to the right page has 2 columns the right (main) column has min width the right (main) column has table inside it that can expend in its data and get wider making all other data in the column expend to the same width as well the sidebar should be on the left side but still floating to the right of the main div it should fit low resolution so the page will be able to add horizontal scroll if needed should work in all major browsers don't use table for constructing the page Can someone help or direct me? Thanks Rani

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  • In LaTeX, is there a way to get long lines along the margins?

    - by Christian Jonassen
    I'm working on a report, and some elements are outside the margins (but some are just barely outside the margins). I was wondering: Is there a way to make two vertical lines, one on each side, along the margins so that one can easily see if it goes outside them? (Googling it, I only found information about margin notes.) A figure is below: |report text goes here| |more text goes also h|ere |and so on and so fort|h It would certainly make correcting these kinds of mistakes very trivial. :) Feel free to post answers that would solve/show this problem in a more "LaTeX-correct" way, if that makes any sense at all.

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  • Vertically Align text in a Div

    - by shinjuo
    I am trying to find the most effective way to align text with a div. I have tried a few things and none seem to work. .testimonialText { position: absolute; left: 15px; top: 15px; width: 150px; height: 309px; vertical-align: middle; text-align: center; font-family: Georgia, "Times New Roman", Times, serif; font-style: italic; padding: 1em 0 1em 0; }

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  • Vertically center CSS techniques don't work in Chrome

    - by at.
    I've gone through stackoverflow questions and a whole bunch of articles on vertically centering text like the following: http://blog.themeforest.net/tutorials/vertical-centering-with-css/ None of the techniques seem to work with the latest version of Chrome. Is that just the nature of Chrome? My text just always appears at the top. It seems that whenever I use 50% or 100% as values for CSS's height or top, nothing happens. I just need a single line of text vertically centered. line-height isn't helpful because I want it centered in the middle of the browser window... I don't know how tall the browser window is going to be. UPDATE: The problem is apparently Foundation 4. Once I delete the following everything works as expected: <link href="/assets/foundation_and_overrides.css?body=1" media="screen" rel="stylesheet" /> Any idea on how to make it work with Foundation 4?

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  • How to Vertically Center Icons on a Line?

    - by jeremy
    What's the best way to center icons on a line when the icons are smaller than the line height? For example (styles inline for easier reading): <div style="line-height: 20px"> <img style="width: 12px; height: 12px;"/> Blah blah blah </div> I want the img to be centered on a single line of the div, above. That is, even if the text wrapped to multiple lines, the image would be centered against a single line. Ideally, the solution would not involve setting margings/paddings on the image and would work even if I didn't know the line-height. Things I've read: How do I vertically align text next to an image with CSS? (deals with case where image is larger, doesn't seem to apply here) Understanding vertical-align

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  • centering image vertically in all resolutions

    - by gnomixa
    I need to be able to center the image vertically for all the common resolutions. A lot of ppl here on SO have already asked this question before, and 90% of then give this tutorial http://www.jakpsatweb.cz/css/css-vertical-center-solution.html as an answer. However, when viewed at my 1280 by 1024 res monitor in FF, it's not centered. And worse yet, it breaks horribly in IE7. So, it's definitely NOT the answer. Am I chasing the impossible dream? The solution has to work for FF and IE 6/7 the solution can be anything that would work, though being a bit of a purist, I would prefer a div over table:)

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  • Request of some opinions about a vertical menu style and some suggestions for the site style [on hold]

    - by AndreaNobili
    I am developing a simple mainly static website using WordPress (because maybe in the future I will add some dynamic content) for a company. The new site have to follow the structure of the old site that requires the presence of a vertical main menu in the left column that contains the link to all the statics pages in the site. This is the old site structure: http://www.saranistri.com/ Now I have installed a new WordPress test site (this is only a test site): http://onofri.org/example/ As you can see in the left columns I have put two main menu vetical widgets that implements a possible choise for the maun menù (the top menù upon the header must be eliminated in the final implementation) I want to know some opinions about: 1) Which of the two version is better? Do you have some additional ideas about the CSS style of this vertical menu? 2) What could I do to give a more professional look to this site? (I know that I have to insert a logo into the header) Tnx Andrea

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  • WPF wrappanel item alignment problem when scrolling

    - by Jayho
    Someone help me out pls. I set a wrapPanel in a listbox itemPanelTemplate, Also, I already set the ScrollViewer.CanContentScroll="True". But why the listbox items are not scrolling up/down by ITEM one by one? The scroll style is still by PIXEL. Is anyone help me? <Grid> <ListBox x:Name="testListbox" ScrollViewer.CanContentScroll="True"> <ListBox.ItemsPanel> <ItemsPanelTemplate> <WrapPanel Width="200" ScrollViewer.CanContentScroll="True"/> </ItemsPanelTemplate> </ListBox.ItemsPanel> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> <ListBoxItem Background="LimeGreen" BorderBrush="Black" BorderThickness="3" ScrollViewer.CanContentScroll="True"> <Image Height="50" Width="80" ScrollViewer.CanContentScroll="True"/> </ListBoxItem> </ListBox> </Grid>

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  • Scroll Position in a Table Body

    - by Craig Walker
    I want to implement infinite scrolling (with an AJAX-based loader) in an HTML table body. My HTML looks something like this: <table> <thead> <tr><th>Column</th></tr> </thead> <tbody> <tr><td>Row 1</td></tr> <tr><td>Row 2</td></tr> </tbody> </table> I get a scroll bar on the <tbody> like so: tbody { height:10em; /* Otherwise the tbody expands to fit all rows */ overflow:auto; } To be able to do anything when the user scrolls to the bottom, I need to be able to get the scroll position of the <tbody>. In all of the (jQuery) infinite scroll implementations I've seen (such as this one), they subtract the content height from the container height and compare it to the .scrollTop() value. Unfortunately this may not work with <tbody>, which is both the viewport and the container for the scrolled content. $("tbody").height() returns the viewable (ie: "shrunken") size, but I don't know how I can get the full (viewable + hidden) size of the table body. (FWIW, $("tbody").scrollTop() returns a "large" number when scrolled to the bottom, exactly as I would expect it to). Is there any way to accomplish this?

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  • DTGridView losing content while scrolling

    - by Wim Haanstra
    I am using DTGridView from the DTKit by Daniel Tull. I implemented it in a very simple ViewController and the test I am doing is to place a button in the last row of the grid, which should add another row to the grid (and therefor moving the button to a row beneath it). The problem is, when I click the button a couple of times and then start scrolling, the grid seems to lose its content. As I am not completly sure this is a bug in the grid, but more in my code, I hope you guys can help me out and track down the bug. First I have my header file, which is quite simple, because this is a test: #import <UIKit/UIKit.h> #import "DTGridView.h" @interface TestController : UIViewController <DTGridViewDelegate, DTGridViewDataSource> { DTGridView* thumbGrid; } @end I declare a DTGridView, which will be my grid, where I want to put content in. Now, my code file: #import "TestController.h" @implementation TestController int rows = 1; - (NSInteger)numberOfRowsInGridView:(DTGridView *)gridView { return rows; } - (NSInteger)numberOfColumnsInGridView:(DTGridView *)gridView forRowWithIndex:(NSInteger)index { if (index == rows - 1) return 1; else return 3; } - (CGFloat)gridView:(DTGridView *)gridView heightForRow:(NSInteger)rowIndex { return 57.0f; } - (CGFloat)gridView:(DTGridView *)gridView widthForCellAtRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { if (rowIndex == rows - 1) return 320.0f; else return 106.6f; } - (DTGridViewCell *)gridView:(DTGridView *)gridView viewForRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { DTGridViewCell *view = [[gridView dequeueReusableCellWithIdentifier:@"thumbcell"] retain]; if (!view) view = [[DTGridViewCell alloc] initWithReuseIdentifier:@"thumbcell"]; if (rowIndex == rows - 1) { UIButton* btnLoadMoreItem = [[UIButton alloc] initWithFrame:CGRectMake(10, 0, 301, 57)]; [btnLoadMoreItem setTitle:[NSString stringWithFormat:@"Button %d", rowIndex] forState:UIControlStateNormal]; [btnLoadMoreItem.titleLabel setFont:[UIFont boldSystemFontOfSize:20]]; [btnLoadMoreItem setBackgroundImage:[[UIImage imageNamed:@"big-green-button.png"] stretchableImageWithLeftCapWidth:10.0 topCapHeight:0.0] forState:UIControlStateNormal]; [btnLoadMoreItem addTarget:self action:@selector(selectLoadMoreItems:) forControlEvents:UIControlEventTouchUpInside]; [view addSubview:btnLoadMoreItem]; [btnLoadMoreItem release]; } else { UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(10,0,100,57)]; label.text = [NSString stringWithFormat:@"%d x %d", rowIndex, columnIndex]; [view addSubview:label]; [label release]; } return [view autorelease]; } - (void) selectLoadMoreItems:(id) sender { rows++; [thumbGrid setNeedsDisplay]; } - (void)viewDidLoad { [super viewDidLoad]; thumbGrid = [[DTGridView alloc] initWithFrame:CGRectMake(0,0, 320, 320)]; thumbGrid.dataSource = self; thumbGrid.gridDelegate = self; [self.view addSubview:thumbGrid]; } - (void)viewDidUnload { [super viewDidUnload]; } - (void)dealloc { [super dealloc]; } @end I implement all the methods for the DataSource, which seem to work. The grid is filled with as many rows as my int 'rows' ( +1 ) has. The last row does NOT contain 3 columns, but just one. That cell contains a button which (when pressed) adds 1 to the 'rows' integer. The problem starts, when it starts reusing cells (I am guessing) and content start disappearing. When I scroll back up, the UILabels I am putting in the cells are gone. Is there some bug, code error, mistake, dumb-ass-move I am missing here? Hope anyone can help.

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  • SWT: scrollable area within a tab

    - by DaveJohnston
    I am trying to add a scrollable area to my tabbed window. So far I have a CTabFolder in a shell. I have added 5 CTabItems to it and everything works as expected. On one of my CTabItems the contents are too big to fit on the screen so I would like to be able to scroll. The contents is a collection of Groups each containing various widgets. So the CTabFolder is created as follows: CTabFolder tabs = new CTabFolder(shell, SWT.BORDER); tabs.setSimple(false); tabs.setUnselectedImageVisible(false); tabs.setUnselectedCloseVisible(false); tabs.setMinimizeVisible(false); tabs.setMaximizeVisible(false); FormData tabsLayoutData = new FormData(); tabsLayoutData.top = new FormAttachment(0, 5); tabsLayoutData.left = new FormAttachment(0, 5); tabsLayoutData.bottom = new FormAttachment(92, 0); tabsLayoutData.right = new FormAttachment(100, -5); tabs.setLayoutData(tabsLayoutData); Then the CTabItem: CTabItem tab = new CTabItem(tabs, SWT.NONE); tab.setText("Role"); Then the contents: Composite tabArea = new Composite(tabs, SWT.V_SCROLL); tabArea.setLayout(new FormLayout()); tab.setControl(tabArea); So the groups contained within the tab are created with tabArea as the parent and everything appears as you would expect. The problem is though that the vertical scroll bar is always present but doesn't seem to do anything. The contents are chopped off at the bottom of the tabArea composite. Is there anything else I need to do to get the scrolling to work properly?

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  • DTGridView losting content while scrolling

    - by Wim Haanstra
    I am using DTGridView from the DTKit by Daniel Tull. I implemented it in a very simple ViewController and the test I am doing is to place a button in the last row of the grid, which should add another row to the grid (and therefor moving the button to a row beneath it). The problem is, when I click the button a couple of times and then start scrolling, the grid seems to lose its content. As I am not completly sure this is a bug in the grid, but more in my code, I hope you guys can help me out and track down the bug. First I have my header file, which is quite simple, because this is a test: #import <UIKit/UIKit.h> #import "DTGridView.h" @interface TestController : UIViewController <DTGridViewDelegate, DTGridViewDataSource> { DTGridView* thumbGrid; } @end I declare a DTGridView, which will be my grid, where I want to put content in. Now, my code file: #import "TestController.h" @implementation TestController int rows = 1; - (NSInteger)numberOfRowsInGridView:(DTGridView *)gridView { return rows; } - (NSInteger)numberOfColumnsInGridView:(DTGridView *)gridView forRowWithIndex:(NSInteger)index { if (index == rows - 1) return 1; else return 3; } - (CGFloat)gridView:(DTGridView *)gridView heightForRow:(NSInteger)rowIndex { return 57.0f; } - (CGFloat)gridView:(DTGridView *)gridView widthForCellAtRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { if (rowIndex == rows - 1) return 320.0f; else return 106.6f; } - (DTGridViewCell *)gridView:(DTGridView *)gridView viewForRow:(NSInteger)rowIndex column:(NSInteger)columnIndex { DTGridViewCell *view = [[gridView dequeueReusableCellWithIdentifier:@"thumbcell"] retain]; if (!view) view = [[DTGridViewCell alloc] initWithReuseIdentifier:@"thumbcell"]; if (rowIndex == rows - 1) { UIButton* btnLoadMoreItem = [[UIButton alloc] initWithFrame:CGRectMake(10, 0, 301, 57)]; [btnLoadMoreItem setTitle:[NSString stringWithFormat:@"Button %d", rowIndex] forState:UIControlStateNormal]; [btnLoadMoreItem.titleLabel setFont:[UIFont boldSystemFontOfSize:20]]; [btnLoadMoreItem setBackgroundImage:[[UIImage imageNamed:@"big-green-button.png"] stretchableImageWithLeftCapWidth:10.0 topCapHeight:0.0] forState:UIControlStateNormal]; [btnLoadMoreItem addTarget:self action:@selector(selectLoadMoreItems:) forControlEvents:UIControlEventTouchUpInside]; [view addSubview:btnLoadMoreItem]; [btnLoadMoreItem release]; } else { UILabel* label = [[UILabel alloc] initWithFrame:CGRectMake(10,0,100,57)]; label.text = [NSString stringWithFormat:@"%d x %d", rowIndex, columnIndex]; [view addSubview:label]; [label release]; } return [view autorelease]; } - (void) selectLoadMoreItems:(id) sender { rows++; [thumbGrid setNeedsDisplay]; } - (void)viewDidLoad { [super viewDidLoad]; thumbGrid = [[DTGridView alloc] initWithFrame:CGRectMake(0,0, 320, 320)]; thumbGrid.dataSource = self; thumbGrid.gridDelegate = self; [self.view addSubview:thumbGrid]; } - (void)viewDidUnload { [super viewDidUnload]; } - (void)dealloc { [super dealloc]; } @end I implement all the methods for the DataSource, which seem to work. The grid is filled with as many rows as my int 'rows' ( +1 ) has. The last row does NOT contain 3 columns, but just one. That cell contains a button which (when pressed) adds 1 to the 'rows' integer. The problem starts, when it starts reusing cells (I am guessing) and content start disappearing. When I scroll back up, the UILabels I am putting in the cells are gone. Is there some bug, code error, mistake, dumb-ass-move I am missing here? Hope anyone can help.

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  • WPF Drag-to-scroll doesn't work correctly.

    - by Garegin
    Hi all, I am tying to realize a drag-to-scroll functionality in my application and have problems on my way. Can anybody help me? I have a ScrollViewer and inside it an ItemsControl and within ItemsTemplate I have a UserControl. I want to drag that UserControl within ItemsControl. I want the ScrollViewer to scroll down, when I am dragging to the boundaries of the ItemsControl. protected override void OnPreviewMouseMove(System.Windows.Input.MouseEventArgs e) { if (this.IsMouseCaptured) { // Get the new mouse position. Point mouseDragCurrentPoint = e.GetPosition(this); if (Math.Abs(mouseDragCurrentPoint.Y - this.ActualHeight) <= 50) { this._scrollStartOffset.Y += 5; _containingScrollViewer.ScrollToVerticalOffset(this._scrollStartOffset.Y); } if (mouseDragCurrentPoint.Y <= 50) { this._scrollStartOffset.Y -= 5; _containingScrollViewer.ScrollToVerticalOffset(this._scrollStartOffset.Y); } } base.OnPreviewMouseMove(e); } When i start dragging by calling DragDrop.DoDragDrop() scrolling don't happens. But when i disable dragging, the ScrollViewer scrolls down dependong on mouse position. Maybe there's something that i don't take into accont about dragging and Capturing the mouse? Thanks for attention. Garegin

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  • Fixed Table Header And Scrolling Body

    - by user2881191
    can Anyone please help me with the example that is on site 'http://mkoryak.github.io/floatThead/examples/inner-scroll/' How Can i Apply the Jquery to the below example. please provide Me the Demo in JSFiddle. I Want to Make My Table Header Fixed With Scrolling (both horizontal and vertical) Body. If Possible I also need to make the last column Fixed as the Header. Please Help Me Reageding the Issue. I Have Been Stuck For a Week. Below Is My test Code For which I need to apply the style as in the above link or any other better approach. Css : #table-container{ background-color :white; overflow:auto; position:absolute; top : 0px; bottom : 18px; width : 100%; z-index: 1; } Jsp : <div id="table-container"> <table id="maintable" style="width: 100%"> <thead> <tr> <th>Col 1</th> <th>Col 2</th> <th>Col 3</th> <th>Col 4</th> <th>Col 5</th> <th>Col 6</th> <th>Col 7</th> <th>Col 8</th> <th>Col 9</th> </tr> </thead> <tbody> <tr> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> </tr> <tr> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> </tr> <tr> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> </tr> <tr> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> </tr> <tr> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> </tr> <tr> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> <td>info</td> </tr> </tbody> </table> </div>

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  • Preventing ListBox scrolling to top when updated

    - by WDZ
    I'm trying to build a simple music player with a ListBox playlist. When adding audio files to the playlist, it first fills the ListBox with the filenames and then (on a separate thread) extracts the ID3 data and overwrites the filenames with the correct Artist - Title information (much like Winamp). But while the ListBox is being updated, it's unscrollable, as it always jumps to the top on every item overwrite. Any way to prevent this? EDIT: The code: public Form1() { //Some initialization code omitted here BindingList<TAG_INFO> trackList = new BindingList<TAG_INFO>(); // The Playlist this.playlist = new System.Windows.Forms.ListBox(); this.playlist.Location = new System.Drawing.Point(12, 12); this.playlist.Name = "playlist"; this.playlist.Size = new System.Drawing.Size(229, 316); this.playlist.DataSource = trackList; } private void playlist_add_Click(object sender, EventArgs e) { //Initialize OpenFileDialog OpenFileDialog opd = new OpenFileDialog(); opd.Filter = "Music (*.WAV; *.MP3; *.FLAC)|*.WAV;*.MP3;*.FLAC|All files (*.*)|*.*"; opd.Title = "Select Music"; opd.Multiselect = true; //Open OpenFileDialog if (DialogResult.OK == opd.ShowDialog()) { //Add opened files to playlist for (int i = 0; opd.FileNames.Length > i; ++i) { if (File.Exists(opd.FileNames[i])) { trackList.Add(new TAG_INFO(opd.FileNames[i])); } } //Initialize BackgroundWorker BackgroundWorker _bw = new BackgroundWorker(); _bw.WorkerReportsProgress = true; _bw.DoWork += new DoWorkEventHandler(thread_trackparser_DoWork); _bw.ProgressChanged += new ProgressChangedEventHandler(_bw_ProgressChanged); //Start ID3 extraction _bw.RunWorkerAsync(); } } void thread_trackparser_DoWork(object sender, DoWorkEventArgs e) { BackgroundWorker _bw = sender as BackgroundWorker; for (int i = 0; i < trackList.Count; ++i) { //Pass extracted tag info to _bw_ProgressChanged for thread-safe playlist entry update _bw.ReportProgress(0,new object[2] {i, BassTags.BASS_TAG_GetFromFile(trackList[i].filename)}); } } void _bw_ProgressChanged(object sender, ProgressChangedEventArgs e) { object[] unboxed = e.UserState as object[]; trackList[(int)unboxed[0]] = (unboxed[1] as TAG_INFO); } EDIT2: Much simpler test case: Try scrolling down without selecting an item. The changing ListBox will scroll to the top again. using System; using System.Windows.Forms; namespace WindowsFormsApplication1 { public class Form1 : Form { private System.ComponentModel.IContainer components = null; protected override void Dispose(bool disposing) { if (disposing && (components != null)) { components.Dispose(); } base.Dispose(disposing); } private void InitializeComponent() { this.components = new System.ComponentModel.Container(); this.listBox1 = new System.Windows.Forms.ListBox(); this.timer1 = new System.Windows.Forms.Timer(this.components); this.SuspendLayout(); // listBox1 this.listBox1.FormattingEnabled = true; this.listBox1.Location = new System.Drawing.Point(0, 0); this.listBox1.Name = "listBox1"; this.listBox1.Size = new System.Drawing.Size(200, 290); // timer1 this.timer1.Enabled = true; this.timer1.Tick += new System.EventHandler(this.timer1_Tick); // Form1 this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F); this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font; this.ClientSize = new System.Drawing.Size(200, 290); this.Controls.Add(this.listBox1); this.Name = "Form1"; this.Text = "Form1"; this.ResumeLayout(false); } private System.Windows.Forms.ListBox listBox1; private System.Windows.Forms.Timer timer1; public Form1() { InitializeComponent(); for (int i = 0; i < 45; i++) listBox1.Items.Add(i); } int tickCounter = -1; private void timer1_Tick(object sender, EventArgs e) { if (++tickCounter > 44) tickCounter = 0; listBox1.Items[tickCounter] = ((int)listBox1.Items[tickCounter])+1; } } static class Program { [STAThread] static void Main() { Application.EnableVisualStyles(); Application.SetCompatibleTextRenderingDefault(false); Application.Run(new Form1()); } } }

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  • Vertically center a fluid image in a fluid container

    - by Ferdy
    I certainly do not want to add to the pile of vertical alignments CSS questions, but I've spent hours trying to find a solution to no avail yet. Here's the situation: I am building a slideshow gallery of images. I want the images to be displayed as large as the user's window allows. So I have this outer placeholder: <section class="photo full"> (Yes, I'm using HTML5 elements). Which has the following CSS: section.photo.full { display:inline-block; width:100%; height:100%; position:absolute; overflow:hidden; text-align:center; } Next, the image is placed inside it. Depending on the orientation of the image, I set either the width or height to 75%, and the other axis to auto: $wide = $bigimage['width'] >= $bigimage['height'] ? true: false; ?> <img src="<?= $bigimage['url'] ?>" width="<?= $wide? "75%" : "auto"?>" height="<?= $wide? "auto" : "75%"?>"/> So, we have a fluid outer container, with inside a fluid image. The horizontal centering of the image works, yet I cannot seem to find a way to vertically center the image within it's container. I have researched centering methods but most assume either the container or image has a known width or height. Then there is the display:table-cell method, which does not seem to work for me either. I'm stuck. I'm looking for a CSS solution, but am open to js solutions too.

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  • Vertically Aligning Elements

    - by Naz
    I'm trying to understand how to center elements within a div. I have this basic code I am working with and am trying to get the 'This is a button' element to be in the center <body> <div style="width:960px;background-color:#d7d7d7;"> <div style=" width:400px; padding:10px; height:auto; background-color:#006699; display:inline-block; "> <p> Vivamus vel sapien. Praesent nisl tortor, laoreet eu, dapibus quis, egestas non, mauris. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Vivamus vel sapien. Praesent nisl tortor, laoreet eu, dapibus quis, egestas non, mauris. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus.</p> </div> <div style=" width:100px; padding:10px; height:auto; background-color:#b1b1b1; float:right; display:inline-block; margin:auto!important; vertical-align:middle; "> <p>This is a button</p> </div> </div> </body> It's essentially 1 div, divided into 2 with text on the left hand side and a 'This is a button' label to be in the center of the right side, but I can;t figure out how to get it to center, I've tried all sorts of methods. All help/advice is appreciated.

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  • Out of memory exception during scrolling of listview

    - by user1761316
    I am using facebook data like postedpicture,profile picture,name,message in my listview.I am getting an OOM error while doing fast scrolling of listview. I am also having scrollviewlistener in my application that loads more data when the scrollbar reaches the bottom of the screen.I just want to know whether I need to change anything in this class. imageLoader.DisplayImage(postimage.get(position).replace(" ", "%20"), postimg) ; I am using the above line to call the method in this imageloader class to set the bitmap to imageview. Here is my imageloader class import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.InputStream; import java.io.OutputStream; import java.net.HttpURLConnection; import java.net.URL; import java.util.Collections; import java.util.Map; import java.util.Stack; import java.util.WeakHashMap; import com.stellent.beerbro.Wall; import android.app.Activity; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Bitmap.Config; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.PorterDuff.Mode; import android.graphics.PorterDuffXfermode; import android.graphics.Rect; import android.graphics.RectF; import android.graphics.drawable.BitmapDrawable; import android.util.Log; import android.widget.ImageView; public class ImageLoader { MemoryCache memoryCache=new MemoryCache(); FileCache fileCache; private Map<ImageView, String> imageViews=Collections.synchronizedMap(new WeakHashMap<ImageView, String>()); public ImageLoader(Context context){ //Make the background thead low priority. This way it will not affect the UI performance photoLoaderThread.setPriority(Thread.NORM_PRIORITY-1); fileCache=new FileCache(context); } // final int stub_id=R.drawable.stub; public void DisplayImage(String url,ImageView imageView) { imageViews.put(imageView, url); System.gc(); // Bitmap bitmap=createScaledBitmap(memoryCache.get(url), 100,100,0); Bitmap bitmap=memoryCache.get(url); // Bitmap bitmaps=bitmap.createScaledBitmap(bitmap, 0, 100, 100); if(bitmap!=null) { imageView.setBackgroundDrawable(new BitmapDrawable(bitmap)); // imageView.setImageBitmap(getRoundedCornerBitmap( bitmap, 10,70,70)); // imageView.setImageBitmap(bitmap); // Log.v("first", "first"); } else { queuePhoto(url, imageView); // Log.v("second", "second"); } } private Bitmap createScaledBitmap(Bitmap bitmap, int i, int j, int k) { // TODO Auto-generated method stub return null; } private void queuePhoto(String url, ImageView imageView) { //This ImageView may be used for other images before. So there may be some old tasks in the queue. We need to discard them. photosQueue.Clean(imageView); PhotoToLoad p=new PhotoToLoad(url, imageView); synchronized(photosQueue.photosToLoad){ photosQueue.photosToLoad.push(p); photosQueue.photosToLoad.notifyAll(); } //start thread if it's not started yet if(photoLoaderThread.getState()==Thread.State.NEW) photoLoaderThread.start(); } public Bitmap getBitmap(String url) { File f=fileCache.getFile(url); //from SD cache Bitmap b = decodeFile(f); if(b!=null) return b; //from web try { Bitmap bitmap=null; URL imageUrl = new URL(url); HttpURLConnection conn = (HttpURLConnection)imageUrl.openConnection(); conn.setConnectTimeout(30000); conn.setReadTimeout(30000); InputStream is=conn.getInputStream(); OutputStream os = new FileOutputStream(f); Utils.CopyStream(is, os); os.close(); bitmap = decodeFile(f); return bitmap; } catch (Exception ex){ ex.printStackTrace(); return null; } }//Lalit //decodes image and scales it to reduce memory consumption private Bitmap decodeFile(File f){ try { //decode image size BitmapFactory.Options o = new BitmapFactory.Options(); o.inJustDecodeBounds = true; BitmapFactory.decodeStream(new FileInputStream(f),null,o); //Find the correct scale value. It should be the power of 2. final int REQUIRED_SIZE=Wall.width; final int REQUIRED_SIZE1=Wall.height; // final int REQUIRED_SIZE=250; // int width_tmp=o.outWidth, height_tmp=o.outHeight; int scale=1; // while(o.outWidth/scale/2>=REQUIRED_SIZE && o.outHeight/scale/2>=REQUIRED_SIZE) //// scale*=2; while(true){ if(width_tmp/2<REQUIRED_SIZE && height_tmp/2<REQUIRED_SIZE1) break; width_tmp/=2; height_tmp/=2; scale*=2; } //decode with inSampleSize BitmapFactory.Options o2 = new BitmapFactory.Options(); o2.inSampleSize=scale; // o2.inSampleSize=2; return BitmapFactory.decodeStream(new FileInputStream(f), null, o2); } catch (FileNotFoundException e) {} return null; } //Task for the queue private class PhotoToLoad { public String url; public ImageView imageView; public PhotoToLoad(String u, ImageView i){ url=u; imageView=i; } } PhotosQueue photosQueue=new PhotosQueue(); public void stopThread() { photoLoaderThread.interrupt(); } //stores list of photos to download class PhotosQueue { private Stack<PhotoToLoad> photosToLoad=new Stack<PhotoToLoad>(); //removes all instances of this ImageView public void Clean(ImageView image) { for(int j=0 ;j<photosToLoad.size();){ if(photosToLoad.get(j).imageView==image) photosToLoad.remove(j); else ++j; } } } class PhotosLoader extends Thread { public void run() { try { while(true) { //thread waits until there are any images to load in the queue if(photosQueue.photosToLoad.size()==0) synchronized(photosQueue.photosToLoad){ photosQueue.photosToLoad.wait(); } if(photosQueue.photosToLoad.size()!=0) { PhotoToLoad photoToLoad; synchronized(photosQueue.photosToLoad){ photoToLoad=photosQueue.photosToLoad.pop(); } Bitmap bmp=getBitmap(photoToLoad.url); memoryCache.put(photoToLoad.url, bmp); String tag=imageViews.get(photoToLoad.imageView); if(tag!=null && tag.equals(photoToLoad.url)){ BitmapDisplayer bd=new BitmapDisplayer(bmp, photoToLoad.imageView); Activity a=(Activity)photoToLoad.imageView.getContext(); a.runOnUiThread(bd); } } if(Thread.interrupted()) break; } } catch (InterruptedException e) { //allow thread to exit } } } PhotosLoader photoLoaderThread=new PhotosLoader(); //Used to display bitmap in the UI thread class BitmapDisplayer implements Runnable { Bitmap bitmap; ImageView imageView; public BitmapDisplayer(Bitmap b, ImageView i){bitmap=b;imageView=i;} public void run() { if(bitmap!=null) imageView.setBackgroundDrawable(new BitmapDrawable(bitmap)); } } public void clearCache() { memoryCache.clear(); fileCache.clear(); } public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, int pixels,int width,int height) { Bitmap output = Bitmap.createBitmap(width,height, Config.ARGB_8888); Canvas canvas = new Canvas(output); final int color = 0xff424242; final Paint paint = new Paint(); final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight()); final RectF rectF = new RectF(rect); final float roundPx = pixels; paint.setAntiAlias(true); canvas.drawARGB(0, 0, 0, 0); paint.setColor(color); canvas.drawRoundRect(rectF, roundPx, roundPx, paint); paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN)); canvas.drawBitmap(bitmap, rect, rect, paint); return output; } }

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  • li element background colors and overflow scrolling

    - by user17753
    I created a simple html source, and applied a small CSS style sheet to it: html { width: 100%; } body { font-family: Calibri, Tahoma, Geneva, sans-serif; padding: 20px; } pre { padding: 0; margin: 0 auto; border: 1px solid #888; font-family: Menlo,Monaco,Consolas,monospace; color: #000; width: 80%; overflow: auto; } pre li { white-space: pre; } ol { margin-top: 0; margin-bottom: 0; /* IE indents via margin-left */ color: #979797; background: #E3E3E3; } .li1 { background: #F5F5F5 } .li2 { background: #eee } I have an ordered list inside a pre-formatted tag. Every other list element is either given the class attribute li1 or li2 (the purpose of which is to alternate the colors). The list elements need the white-space: pre because the white space before and after the text node is important. The pre is to be 80% of the containing element (which ends up being 80% of the window's width). In the event of overflow in the x dimension, I want scrolling. I did all this in the above CSS, and it almost works. The issue I am having is that the background colors of the list elements don't extend with the content. They seem to be capped to the original width of the pre and/or ol element as demonstrated in the following picture where I scroll all the way right as possible: I tinkered with the CSS for a while, but I cannot determine the root cause for this or the fix. Looking for some advice on this one, thanks. Complete source with the issue is as below, NOTE: to would-be editors of the below code the pre element is intended to be on a single line as it's pre-formatted text, and formatting it otherwise would change things. <!DOCTYPE html> <html> <head> <meta http-equiv="content-type" content="text/html; charset=utf-8"> <title>Test Site</title> <style type="text/css"> html { width: 100%; } body { font-family: Calibri, Tahoma, Geneva, sans-serif; padding: 20px; } pre { padding: 0; margin: 0 auto; border: 1px solid #888; font-family: Menlo,Monaco,Consolas,monospace; color: #000; width: 80%; overflow: auto; } pre li { white-space: pre; } ol { margin-top: 0; margin-bottom: 0; /* IE indents via margin-left */ color: #979797; background: #E3E3E3; } .li1 { background: #F5F5F5 } .li2 { background: #eee } </style> </head> <body> <pre class="php"><ol><li class="li1">pre a &#123; text-decoration: none &#125;</li><li class="li2">pre a:hover &#123; background: #C8C8C8 }</li><li class="li1">pre li &#123; white-space: pre; &#125;</li><li class="li2">&nbsp;</li><li class="li1">.php ol &#123; margin-top: 0; margin-bottom: 0; /* IE indents via margin-left */</li><li class="li2"> color: #979797; background: #E3E3E3; }</li><li class="li1">&nbsp;</li><li class="li2">&nbsp;</li><li class="li1">&nbsp;</li><li class="li2">.php .li1 &#123; background: #F5F5F5 }</li><li class="li1">.php .li2 &#123; background: #eee }</li><li class="li2">&nbsp;</li><li class="li1">&nbsp;</li><li class="li2">.php .st0 &#123; color: #C0C } /* string content */</li><li class="li1">.php .st_h &#123; color: #F0C } /* string content single quoted */</li><li class="li2">.php .sy0 &#123; color: #000 } /* semi-colon, operators */ </li><li class="li1">.php .br0 &#123; color: #000 } /* parens */</li><li class="li2">.php .kw2 &#123; color: #00F } /* php tags */</li><li class="li1">.php .sy1 &#123; color: #00F } /* php tags */</li><li class="li2">.php .nu0 &#123; color: #F00 } /* numbers */</li><li class="li1">.php .kw3 &#123; color: #096 } /* core language functions */</li><li class="li2">.php .re0 &#123; color: #09F; font-weight: bold; } /* variables */</li><li class="li1">.php .kw1 &#123; color: #069; font-weight: bold; } /* control statements? */</li><li class="li2">.php .kw4 &#123; color: #069; font-weight: bold; } /* bool? */</li><li class="li1">.php .co1 &#123; color: #FF8400 } /* Forward slash comments */</li></ol></pre> </body> </html>

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  • Parallax backgrounds in OpenGL ES on the iPhone

    - by Scott
    I've got basically a 2d game on the iPhone and I'm trying to set up multiple backgrounds that scroll at different speeds (known as parallax backgrounds). So my thought was to just stick the backgrounds BEHIND the foreground using different z-coordinate planes, and just make them bigger than the foreground (in size) to accommodate, so that the whole thing can be scrolled (just at a different speed). And (as far as I know) I basically implemented that. The only problem is that it seems to entirely ignore whatever z-value I give it, or rather it just zeroes all of them. I see the background (I've only tested ONE background so far, to keep it simple...so for now I just have a foreground and I want one background scrolling at a different speed), but it scrolls 1:1 with my foreground, so it obviously doesn't look right, and most of it is cut off (cause it's bigger). And I've tried various z-values for the background and various near/far clipping planes...it's always the same. I'm probably just doing one simple thing wrong, but I can't figure it out. I'm wondering if it has to do with me using only 2 coordinates in glVertexPointer for the foreground? (Of course for the background I AM passing in 3) I'll post some code: This is some initial setup: glMatrixMode(GL_PROJECTION); glLoadIdentity(); glOrthof(-1.0f, 1.0f, -1.5f, 1.5f, -10.0f, 10.0f); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); glEnableClientState(GL_VERTEX_ARRAY); //glEnableClientState(GL_COLOR_ARRAY); glEnableClientState(GL_TEXTURE_COORD_ARRAY); //transparency glEnable (GL_BLEND); glBlendFunc (GL_ONE, GL_ONE_MINUS_SRC_ALPHA); A little bit about my foreground's float array....it's interleaved. For my foreground it goes vertex x, vertex y, texture x, texture y, repeat. This all works just fine. This is my FOREGROUND rendering: glVertexPointer(2, GL_FLOAT, 4*sizeof(GLfloat), texes); <br> glTexCoordPointer(2, GL_FLOAT, 4*sizeof(GLfloat), (GLvoid*)texes + 2*sizeof(GLfloat)); <br> glDrawArrays(GL_TRIANGLES, 0, indexCount / 4); BACKGROUND rendering: Same drill here except this time it goes vertex x, vertex y, vertex z, texture x, texture y, repeat. Note the z value this time. I did make sure the data in this array was correct while debugging (getting the right z values). And again, it shows up...it's just not going far back in the distance like it should. glVertexPointer(3, GL_FLOAT, 5*sizeof(GLfloat), b1Texes); glTexCoordPointer(2, GL_FLOAT, 5*sizeof(GLfloat), (GLvoid*)b1Texes + 3*sizeof(GLfloat)); glDrawArrays(GL_TRIANGLES, 0, b1IndexCount / 5); And to move my camera, I just do a simple glTranslatef(x, y, 0.0f); I'm not understanding what I'm doing wrong cause this seems like the most basic 3D function imaginable...things further away are smaller and don't move as fast when the camera moves. Not the case for me. Seems like it should be pretty basic and not even really be affected by my projection and all that (though I've even tried doing glFrustum just for fun, no success). Please help, I feel like it's just one dumb thing. I will post more code if necessary.

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  • Why Is Vertical Resolution Monitor Resolution so Often a Multiple of 360?

    - by Jason Fitzpatrick
    Stare at a list of monitor resolutions long enough and you might notice a pattern: many of the vertical resolutions, especially those of gaming or multimedia displays, are multiples of 360 (720, 1080, 1440, etc.) But why exactly is this the case? Is it arbitrary or is there something more at work? Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites. The Question SuperUser reader Trojandestroy recently noticed something about his display interface and needs answers: YouTube recently added 1440p functionality, and for the first time I realized that all (most?) vertical resolutions are multiples of 360. Is this just because the smallest common resolution is 480×360, and it’s convenient to use multiples? (Not doubting that multiples are convenient.) And/or was that the first viewable/conveniently sized resolution, so hardware (TVs, monitors, etc) grew with 360 in mind? Taking it further, why not have a square resolution? Or something else unusual? (Assuming it’s usual enough that it’s viewable). Is it merely a pleasing-the-eye situation? So why have the display be a multiple of 360? The Answer SuperUser contributor User26129 offers us not just an answer as to why the numerical pattern exists but a history of screen design in the process: Alright, there are a couple of questions and a lot of factors here. Resolutions are a really interesting field of psychooptics meeting marketing. First of all, why are the vertical resolutions on youtube multiples of 360. This is of course just arbitrary, there is no real reason this is the case. The reason is that resolution here is not the limiting factor for Youtube videos – bandwidth is. Youtube has to re-encode every video that is uploaded a couple of times, and tries to use as little re-encoding formats/bitrates/resolutions as possible to cover all the different use cases. For low-res mobile devices they have 360×240, for higher res mobile there’s 480p, and for the computer crowd there is 360p for 2xISDN/multiuser landlines, 720p for DSL and 1080p for higher speed internet. For a while there were some other codecs than h.264, but these are slowly being phased out with h.264 having essentially ‘won’ the format war and all computers being outfitted with hardware codecs for this. Now, there is some interesting psychooptics going on as well. As I said: resolution isn’t everything. 720p with really strong compression can and will look worse than 240p at a very high bitrate. But on the other side of the spectrum: throwing more bits at a certain resolution doesn’t magically make it better beyond some point. There is an optimum here, which of course depends on both resolution and codec. In general: the optimal bitrate is actually proportional to the resolution. So the next question is: what kind of resolution steps make sense? Apparently, people need about a 2x increase in resolution to really see (and prefer) a marked difference. Anything less than that and many people will simply not bother with the higher bitrates, they’d rather use their bandwidth for other stuff. This has been researched quite a long time ago and is the big reason why we went from 720×576 (415kpix) to 1280×720 (922kpix), and then again from 1280×720 to 1920×1080 (2MP). Stuff in between is not a viable optimization target. And again, 1440P is about 3.7MP, another ~2x increase over HD. You will see a difference there. 4K is the next step after that. Next up is that magical number of 360 vertical pixels. Actually, the magic number is 120 or 128. All resolutions are some kind of multiple of 120 pixels nowadays, back in the day they used to be multiples of 128. This is something that just grew out of LCD panel industry. LCD panels use what are called line drivers, little chips that sit on the sides of your LCD screen that control how bright each subpixel is. Because historically, for reasons I don’t really know for sure, probably memory constraints, these multiple-of-128 or multiple-of-120 resolutions already existed, the industry standard line drivers became drivers with 360 line outputs (1 per subpixel). If you would tear down your 1920×1080 screen, I would be putting money on there being 16 line drivers on the top/bottom and 9 on one of the sides. Oh hey, that’s 16:9. Guess how obvious that resolution choice was back when 16:9 was ‘invented’. Then there’s the issue of aspect ratio. This is really a completely different field of psychology, but it boils down to: historically, people have believed and measured that we have a sort of wide-screen view of the world. Naturally, people believed that the most natural representation of data on a screen would be in a wide-screen view, and this is where the great anamorphic revolution of the ’60s came from when films were shot in ever wider aspect ratios. Since then, this kind of knowledge has been refined and mostly debunked. Yes, we do have a wide-angle view, but the area where we can actually see sharply – the center of our vision – is fairly round. Slightly elliptical and squashed, but not really more than about 4:3 or 3:2. So for detailed viewing, for instance for reading text on a screen, you can utilize most of your detail vision by employing an almost-square screen, a bit like the screens up to the mid-2000s. However, again this is not how marketing took it. Computers in ye olden days were used mostly for productivity and detailed work, but as they commoditized and as the computer as media consumption device evolved, people didn’t necessarily use their computer for work most of the time. They used it to watch media content: movies, television series and photos. And for that kind of viewing, you get the most ‘immersion factor’ if the screen fills as much of your vision (including your peripheral vision) as possible. Which means widescreen. But there’s more marketing still. When detail work was still an important factor, people cared about resolution. As many pixels as possible on the screen. SGI was selling almost-4K CRTs! The most optimal way to get the maximum amount of pixels out of a glass substrate is to cut it as square as possible. 1:1 or 4:3 screens have the most pixels per diagonal inch. But with displays becoming more consumery, inch-size became more important, not amount of pixels. And this is a completely different optimization target. To get the most diagonal inches out of a substrate, you want to make the screen as wide as possible. First we got 16:10, then 16:9 and there have been moderately successful panel manufacturers making 22:9 and 2:1 screens (like Philips). Even though pixel density and absolute resolution went down for a couple of years, inch-sizes went up and that’s what sold. Why buy a 19″ 1280×1024 when you can buy a 21″ 1366×768? Eh… I think that about covers all the major aspects here. There’s more of course; bandwidth limits of HDMI, DVI, DP and of course VGA played a role, and if you go back to the pre-2000s, graphics memory, in-computer bandwdith and simply the limits of commercially available RAMDACs played an important role. But for today’s considerations, this is about all you need to know. Have something to add to the explanation? Sound off in the the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.     

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  • How can I support scrolling when using batched rendering for my tiles?

    - by dardanel
    I have tiled map 100*75 and tiles are 32*32 pixel.I want to use batching for performance .I don't figure it out , because of my game needs scrolling and every frame i draw 22*16 tiles (my screen is 20*16 tile) .I thought that batching tiles for every frame .Is it good or any suggestion? edit :to more clarify I want to use occlusion culling and batching at the same time.I thought that drawing only visible areas and batching them together .But there is a something i couldn't figure out .When scrolling screen with translate matrix , if one row become invisible , I bind new row and batch them again.Every batched objects needs to buffer again.So I batch tiles and buffer to VBO every time when one row become invisible .I don't know these way is efficient or not .This is my question .And i am open to any suggestions.

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