bitmapimage

问题 UPDATES : Even if i don't retrieve images from cache, i tried to retrieve via Drawable where i stored all the 18 images in the "drawable-mdpi" folder. Still, a blank screen was display. I was able to retrieved images from the server and save the image (.GIF) into the cache. However, when i need to load that image from cache, the image doesn't show up on screen. Here is the codes that does the work: File cacheDir = context.getCacheDir(); File cacheMap = new File(cacheDir, smallMapImageNames

问题 There are a few samples to do this but they are for Windows Phone 8.0 or 8.1 Silverlight. But how can you do this for Windows Phone 8.1 Runtime? 回答1: You cannot extract the pixels from a Windows.UI.Xaml.Media.Imaging.BitmapImage. The most general solution is to use a WriteableBitmap instead of a BitmapImage. These classes are both BitmapSources and can be used almost interchangeably. The WriteableBitmap provides access to its pixel data via its PixelBuffer property: byte[] pixelArray =

问题 I have a perfectly working code that creates 32bpp bitmap and I need to change it so that 8bpp bitmap is created. Here's the piece of code that creates 32bpp bitmap, draws into it, then it creates a bitmap file and store it into the vector of bytes: // prepare bitmap: BYTE* bitmap_data = NULL; HDC hDC = GetDC(NULL); HDC memHDC = CreateCompatibleDC(hDC); BITMAPINFO bmi; memset(&bmi, 0, sizeof(BITMAPINFO)); bmi.bmiHeader.biSize = sizeof(BITMAPINFOHEADER); bmi.bmiHeader.biWidth = desiredWidth; /

问题 BitmapImage bitmapImage = new BitmapImage(new Uri("arka_projects_as_logo.png", UriKind.Relative)); Image uiElement = new Image() { Source = bitmapImage }; ScaleTransform t = new ScaleTransform() { ScaleX = 0.2, ScaleY = 0.2 }; WriteableBitmap writeableBitmap = new WriteableBitmap(uiElement,t); I want to insert the result of this conversions (writeableBitmap) into System.Windows.Controls.Image. When I do this: Image arkaImage = new Image() { Source = writeableBitmap }; arkaImage isn't shown at

问题 How are you supposed to dispose of a BitmapSource ? // this wont work because BitmapSource doesnt implement IDisposable using(BitmapSource bitmap = new BitmapImage(new Uri("myimage.png"))) { } 回答1: You do not have to Dispose() a BitmapSource. Unlike some other "image" classes in the Framework, it does not wrap any native resources. Just let it go out of scope, and the garbage collector will free its memory. 来源： https://stackoverflow.com/questions/1591996/proper-way-to-dispose-a-bitmapsource

问题 This is the sequence part of this question: Combining 2 Images overlayed so the problem is: if the image size is too big - it'll got an exception (out of memory exception) what i want is, to handle even if the handset got the lower spec hardware, it doesn't go to that exception (but it'll take a longer time to process the image) is it possible to do that? the code snippet is like this: public static Bitmap overlay(Bitmap bmp1, Bitmap bmp2) { Bitmap bmOverlay = Bitmap.createBitmap(bmp1

问题 I'm trying to reload an image (System.Windows.Controls.Image) I display in WPF. I set the source like this: ScreenAtco01Image.Source = new BitmapImage(new Uri(@"Y:/screenshots/naratco08-0-0-screenshot.png", UriKind.RelativeOrAbsolute)); I made a button, which should force a reload of this image (it changes on disk every second). I have tried resetting the Source, but that doesn't do anything. However if I change the Source to a different image, this different image does get loaded. It seems

问题 I am having some trouble creating a BitmapImage from a MemoryStream from png and gif bytes obtained from a web request. The bytes seem to be downloaded fine and the BitmapImage object is created without issue however the image is not actually rendering on my UI. The problem only occurs when the downloaded image is of type png or gif (works fine for jpeg). Here is code that demonstrates the problem: var webResponse = webRequest.GetResponse(); var stream = webResponse.GetResponseStream(); if

问题 I am having some trouble creating a BitmapImage from a MemoryStream from png and gif bytes obtained from a web request. The bytes seem to be downloaded fine and the BitmapImage object is created without issue however the image is not actually rendering on my UI. The problem only occurs when the downloaded image is of type png or gif (works fine for jpeg). Here is code that demonstrates the problem: var webResponse = webRequest.GetResponse(); var stream = webResponse.GetResponseStream(); if

问题 I want load huge image from url and show on my device. I read this post for doing this. In that example they use native drawable but I want get image from server. I am using this code private void getBitmap(ImageView imageView,final String url){ mBitmapOptions = new BitmapFactory.Options(); mBitmapOptions.inJustDecodeBounds = true; URL mUrl = null; InputStream is= null; try { mUrl = new URL(url); is = mUrl.openStream(); } catch (MalformedURLException e) { e.printStackTrace(); } catch