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2014/10/15 ¤U¤È 10:13:13
iphone Programming Glossary: redrawHow would I tint an image programatically on the iPhone? http://stackoverflow.com/questions/1117211/how-would-i-tint-an-image-programatically-on-the-iphone property let's call it overlayColor to hold the blend color and a custom setter that forces a redraw when the color changes. Something like this void setOverlayColor UIColor newColor if overlayColor overlayColor.. the actual drawing to only the area passed in to drawRect but since the background image has to be redrawn each time the color changes it's likely the whole thing will need refreshing. To use it create an instance..
How can i change the color of pagination dots of UIPageControl? http://stackoverflow.com/questions/2942636/how-can-i-change-the-color-of-pagination-dots-of-uipagecontrol it. Future improvements Resize the dots to fit the current bounds if there are too many. Don't redraw the entire view in drawRect Example use CGRect f CGRectMake 0 0 320 20 PageControl pageControl PageControl..
How do I reset after a UIScrollView zoom? http://stackoverflow.com/questions/448285/how-do-i-reset-after-a-uiscrollview-zoom like it does when I return the graph from viewForZoomingInScrollView. However the Graph redraws itself at the new zoom level and I want to reset the transform scale to 1x1 so that the next time the.. at the correct scale but the actual act of zooming looks bad. So first how do I allow the graph to redraw itself at the standard scale of 1x1 after zooming and how do I have a smooth zoom throughout Edit New.. apply a transform to it. This transform provides a smooth scaling of the view without having to redraw it each frame. At the end of the zoom operation your delegate method scrollViewDidEndZooming withView..
Dispelling the UIImage imageNamed: FUD http://stackoverflow.com/questions/924740/dispelling-the-uiimage-imagenamed-fud and likely for longer than you need it. However if you do have a large image that you need to redraw often then there are alternatives although the one I would recommend primarily is to avoid redrawing.. redraw often then there are alternatives although the one I would recommend primarily is to avoid redrawing that large image . With respect to the general behavior of the cache it does cache based on filename..
How would I tint an image programatically on the iPhone? http://stackoverflow.com/questions/1117211/how-would-i-tint-an-image-programatically-on-the-iphone and override the drawRect method. Your class needs a UIColor property let's call it overlayColor to hold the blend color and a custom setter that forces a redraw when the color changes. Something like this void setOverlayColor UIColor newColor if overlayColor overlayColor release overlayColor newColor retain self setNeedsDisplay.. Ordinarily to optimize the drawing you would restrict the actual drawing to only the area passed in to drawRect but since the background image has to be redrawn each time the color changes it's likely the whole thing will need refreshing. To use it create an instance of the object then set the image property inherited..
How can i change the color of pagination dots of UIPageControl? http://stackoverflow.com/questions/2942636/how-can-i-change-the-color-of-pagination-dots-of-uipagecontrol seems to work. Let me know if you run into any problems with it. Future improvements Resize the dots to fit the current bounds if there are too many. Don't redraw the entire view in drawRect Example use CGRect f CGRectMake 0 0 320 20 PageControl pageControl PageControl alloc initWithFrame f autorelease pageControl.numberOfPages..
How do I reset after a UIScrollView zoom? http://stackoverflow.com/questions/448285/how-do-i-reset-after-a-uiscrollview-zoom in and out of the UIScrollView I want the graph to resize dynamically like it does when I return the graph from viewForZoomingInScrollView. However the Graph redraws itself at the new zoom level and I want to reset the transform scale to 1x1 so that the next time the user zooms the transform starts from the current view. If.. it's suddenly at 4x. When I finish the zoom it ends up at the correct scale but the actual act of zooming looks bad. So first how do I allow the graph to redraw itself at the standard scale of 1x1 after zooming and how do I have a smooth zoom throughout Edit New findings The error seems to be CALayer retainCount message.. in the viewForZoomingInScrollView delegate method and apply a transform to it. This transform provides a smooth scaling of the view without having to redraw it each frame. At the end of the zoom operation your delegate method scrollViewDidEndZooming withView atScale will be called and give you a chance to do a more..
Dispelling the UIImage imageNamed: FUD http://stackoverflow.com/questions/924740/dispelling-the-uiimage-imagenamed-fud here except to have a cached version of the image hanging around and likely for longer than you need it. However if you do have a large image that you need to redraw often then there are alternatives although the one I would recommend primarily is to avoid redrawing that large image . With respect to the general behavior of.. it. However if you do have a large image that you need to redraw often then there are alternatives although the one I would recommend primarily is to avoid redrawing that large image . With respect to the general behavior of the cache it does cache based on filename so two instances of imageNamed with the same name should..
How would I tint an image programatically on the iPhone? http://stackoverflow.com/questions/1117211/how-would-i-tint-an-image-programatically-on-the-iphone class needs a UIColor property let's call it overlayColor to hold the blend color and a custom setter that forces a redraw when the color changes. Something like this void setOverlayColor UIColor newColor if overlayColor overlayColor release overlayColor.. you would restrict the actual drawing to only the area passed in to drawRect but since the background image has to be redrawn each time the color changes it's likely the whole thing will need refreshing. To use it create an instance of the object..
Checkbox image toggle in UITableViewCell http://stackoverflow.com/questions/1171476/checkbox-image-toggle-in-uitableviewcell UIControlEventTouchUpInside Set the UIImageView's image property to update the image that will trigger the redraw without side effects. void toggleImage selected selected imageView.image selected selectedImage normalImage Use NSNotification..
Drawing incrementally in a UIView (iPhone) http://stackoverflow.com/questions/1798414/drawing-incrementally-in-a-uiview-iphone I have understood so far every time I draw something in the drawRect of a UIView the whole context is erased and then redrawn. So I have to do something like this to draw a series of dots Method A drawing everything on every call void drawRect CGRect.. drawAtPoint CGPointZero draw the cached image EDIT After all I combined one of the methods mention below with redrawing only in the new rect. The result is FAST METHOD void addDotAt CGPoint point if myPoints count kMaxPoints Drop drop Drop.. setNeedsDisplayInRect CGRectMake drop.point.x drop.dropSize 2 drop.point.y drop.dropSize 2 drop.dropSize drop.dropSize redraw void drawRect CGRect rect CGContextRef context UIGraphicsGetCurrentContext CGContextDrawImage context self.bounds maskRef..
real time plotting on iPhone using core plot? http://stackoverflow.com/questions/2399836/real-time-plotting-on-iphone-using-core-plot values to display. As these data points come in call reloadData on the Core Plot graph or just the particular plot to redraw the graph passing in the array you just added a value to in response to the numbersForPlot field recordIndexRange delegate..
iPhone: Changing CGImageAlphaInfo of CGImage http://stackoverflow.com/questions/2457116/iphone-changing-cgimagealphainfo-of-cgimage 1344 bytes row. The list of supported pixel formats definitely does not support this combination. It appears I need to redraw the image and move the alpha channel information to kCGImageAlphaPremultipliedFirst or kCGImageAlphaPremultipliedLast ...
How to detect iPhone movement in space using accelerometer? http://stackoverflow.com/questions/2674717/how-to-detect-iphone-movement-in-space-using-accelerometer using accelerometer. As an example if you draw a circle with your hand holding the iPhone the app would be able to redraw it on the screen. This could also work with squares or even more complicated shapes. The only example of application I've..
How can i change the color of pagination dots of UIPageControl? http://stackoverflow.com/questions/2942636/how-can-i-change-the-color-of-pagination-dots-of-uipagecontrol into any problems with it. Future improvements Resize the dots to fit the current bounds if there are too many. Don't redraw the entire view in drawRect Example use CGRect f CGRectMake 0 0 320 20 PageControl pageControl PageControl alloc initWithFrame..
Why animating custom CALayer properties causes other properties to be nil during animation? http://stackoverflow.com/questions/4016496/why-animating-custom-calayer-properties-causes-other-properties-to-be-nil-during circleLayer.radius NSNumber numberWithDouble 50.0 drawInContext gets called as expected during the animation to redraw the circle however the tint is set to nil as soon as the animation starts and gets back to its original value when the animation..
How do I reset after a UIScrollView zoom? http://stackoverflow.com/questions/448285/how-do-i-reset-after-a-uiscrollview-zoom graph to resize dynamically like it does when I return the graph from viewForZoomingInScrollView. However the Graph redraws itself at the new zoom level and I want to reset the transform scale to 1x1 so that the next time the user zooms the transform.. the zoom it ends up at the correct scale but the actual act of zooming looks bad. So first how do I allow the graph to redraw itself at the standard scale of 1x1 after zooming and how do I have a smooth zoom throughout Edit New findings The error.. delegate method and apply a transform to it. This transform provides a smooth scaling of the view without having to redraw it each frame. At the end of the zoom operation your delegate method scrollViewDidEndZooming withView atScale will be called..
Quartz 2D drawRect method (iPhone) http://stackoverflow.com/questions/716351/quartz-2d-drawrect-method-iphone 2D . Is drawRect meant to simply be a hook in which to execute your drawing code Or is this method supposed to also redraw regions that are damaged and need repainting Can I just draw my stuff once and then it sticks or must I repaint the whole.. into the layer. The layer acts like a rectangular texture so when you move the layer backed view or cover it no redraw is needed the texture is just moved to that location via the GPU. Unless you set the needsDisplayOnBoundsChange property.. will simply scale the contents. This may lead to blurry graphics within your view or layer so you may want to force a redraw in this case. setNeedsDisplay will trigger a manual redraw of the view's or layer's content and a subsequent recaching of..
UIView: how to do non-destructive drawing? http://stackoverflow.com/questions/865636/uiview-how-to-do-non-destructive-drawing without entirely replacing it Based on answers received here and elsewhere here is the deal. You should be prepared to redraw the entire rectangle whenever drawRect is called. You cannot prevent the contents from being erased by doing the following..
Dispelling the UIImage imageNamed: FUD http://stackoverflow.com/questions/924740/dispelling-the-uiimage-imagenamed-fud the image hanging around and likely for longer than you need it. However if you do have a large image that you need to redraw often then there are alternatives although the one I would recommend primarily is to avoid redrawing that large image ... that you need to redraw often then there are alternatives although the one I would recommend primarily is to avoid redrawing that large image . With respect to the general behavior of the cache it does cache based on filename so two instances..
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