argb

问题 I have RGB color value and alpha value. How can I get new RGB value assuming that I have white backgound and alpha is applied? 回答1: The formula to be applied to each of the color channels is the following: cr = cf * af + cb * ab * (1 - af) where cr is the resulting color of the pixel, cf is the foreground color, cb the background color, af foreground alpha and ab background alpha. Note that often color values are stored already premultiplied by alpha in which case the formula simplifies to cr

问题 I have RGB color value and alpha value. How can I get new RGB value assuming that I have white backgound and alpha is applied? 回答1: The formula to be applied to each of the color channels is the following: cr = cf * af + cb * ab * (1 - af) where cr is the resulting color of the pixel, cf is the foreground color, cb the background color, af foreground alpha and ab background alpha. Note that often color values are stored already premultiplied by alpha in which case the formula simplifies to cr

问题 I am trying to access the raw data of a Bitmap in ARGB_8888 format on Android, using the copyPixelsToBuffer and copyPixelsFromBuffer methods. However, invocation of those calls seems to always apply the alpha channel to the rgb channels. I need the raw data in a byte[] or similar (to pass through JNI; yes, I know about bitmap.h in Android 2.2, cannot use that). Here is a sample: // Create 1x1 Bitmap with alpha channel, 8 bits per channel Bitmap one = Bitmap.createBitmap(1,1,Bitmap.Config.ARGB

问题 I am trying to access the raw data of a Bitmap in ARGB_8888 format on Android, using the copyPixelsToBuffer and copyPixelsFromBuffer methods. However, invocation of those calls seems to always apply the alpha channel to the rgb channels. I need the raw data in a byte[] or similar (to pass through JNI; yes, I know about bitmap.h in Android 2.2, cannot use that). Here is a sample: // Create 1x1 Bitmap with alpha channel, 8 bits per channel Bitmap one = Bitmap.createBitmap(1,1,Bitmap.Config.ARGB

问题 I am trying to access the raw data of a Bitmap in ARGB_8888 format on Android, using the copyPixelsToBuffer and copyPixelsFromBuffer methods. However, invocation of those calls seems to always apply the alpha channel to the rgb channels. I need the raw data in a byte[] or similar (to pass through JNI; yes, I know about bitmap.h in Android 2.2, cannot use that). Here is a sample: // Create 1x1 Bitmap with alpha channel, 8 bits per channel Bitmap one = Bitmap.createBitmap(1,1,Bitmap.Config.ARGB

问题 I have to read a 24bpp Bitmap and convert each pixel from RGB24 to ARGB16 . I used the following code, #define ARGB16(a, r, g, b) ( ((a) << 15) | (r)|((g)<<5)|((b)<<10)) But I am not getting the required Output. Any help would be highly appreciated. 回答1: Break it up. Let's continue to use macros: #define TRUNCATE(x) ((x) >> 3) #define ARGB16(a,r,g,b) ((a << 15) | (TRUNCATE(r) << 10) | (TRUNCATE(g) << 5) | TRUNCATE(b))) This assumes the alpha is just a single bit. 回答2: Since the RGB values are

问题 I have some sliders in my application that allows the user to change ARGB colors, however I need to convert these values to a hex value like 0xff000000, which is solid black. This is what I have so far: protected int toHex(Color col) { String as = pad(Integer.toHexString(col.getAlpha())); String rs = pad(Integer.toHexString(col.getRed())); String gs = pad(Integer.toHexString(col.getGreen())); String bs = pad(Integer.toHexString(col.getBlue())); String hex = "0x" + as + rs + gs + bs; return

问题 How to change it to store message into least significant bit of R,G,B. The code below only embed message into Alpha (0~7bit) embedInteger deals with embedding the length of the message in the first 32 pixels. embedByte embeds your message characters, one by one. Every time it is called upon, it takes as an input the next character in your message in byte form, b[i]. There, it embeds one bit per pixel, for a total of 8 bits per byte. private void embedMessage(BufferedImage img, byte[] mess) {

问题 I have a PNG file with transparency that is loaded and stored in a BufferedImage . I need this BufferedImage to be of TYPE_INT_ARGB . However, when I use getType() the returned value is 0 ( TYPE_CUSTOM ) instead of 2 ( TYPE_INT_ARGB ). This is how I load the .png : public File img = new File("imagen.png"); public BufferedImage buffImg = new BufferedImage(240, 240, BufferedImage.TYPE_INT_ARGB); try { buffImg = ImageIO.read(img ); } catch (IOException e) { } System.out.Println(buffImg.getType()

问题 When I try to create a ARGB32 QImage from a reinterpret_cast<uchar*>(quint32*) using the QImage constructor the Image looses its color and alpha channel and the resulting QImage is grayscale! The grayscale image is displayed as expected, if I was trying to display it in grayscale. So I know the scaling and indexing of ushort data to the quint32 array went well, but what is going wrong? A Qt forum post suggested to do it the way I am doing it (as far as I can see), but maybe behavior has