alpha

I want to display an image with alpha with a specified transparency, but can't figure out how to do it. To elaborate on how I'm struggling with this, the blurb below is a slightly modified hunk of code from this SO answer , but if you run it, you'll see that "image" loses it's native alpha, while the alpha of "image2" never changes! Yuck. #!/usr/bin/env python import pygame, sys pygame.init() window = pygame.display.set_mode((200, 200)) background = pygame.Surface((window.get_size())) background.fill((255, 255, 255)) image = image2 = pygame.image.load('alpha.png') image = image.convert() rect

I have an PNG image with alpha, I need to convert it to BMP to be loaded to my OpenGL application. However, BMP has only 1 option for 32-bit, that is XRBG where 'X' is just an extra byte for padding purpose (4-byte alignment). The question is how to ultilise this 'X' byte to contain alpha channel, so that the BMP (32-bit XRGB) can be loaded to GL application with transparent pixels? Maybe I have to make my own tool to do this conversion? What I need is RGBA, and not 'XRGB' or 'ARGB', do I have to read the XRGB BMP file and scan pixel by pixel to convert to RGBA? Which is the best way in VC++

While doing some tests with .gif animations in MATLAB I realised that somehow I can't read the transparency of the gif. Example: (Original source of the gif) If I do [img,cmap]=imread('Finnandjake.gif'); img is 4D with a redundant 3rd dimension (weird). After squeezing it ( img=squeeze(img); ), if I show it ( imshow(img(:,:,30),cmap) ): The transparency is gone, using another color from the image as background, thus deleting features. However [img,cmap,alpha]=imread('Finnandjake.gif'); returns an empty alpha . Obviously the information of the alpha is in the image somewhere, how can I read it

I have a UIView with an alpha of .5 I have added a subview with an alpha of 1. The subview seems to inherit the alpha value of the parent. Is there a way to make the subview more opaque than its parent view? code looks like this: CGRect promptFrame = CGRectMake(55, 80, 180, 50); UIView *inputPrompt = [[UIView alloc] initWithFrame: promptFrame]; [inputPrompt setBackgroundColor: [UIColor darkGrayColor]]; [inputPrompt setAlpha: .5]; inputPrompt.layer.cornerRadius = 8; inputPrompt.layer.masksToBounds = YES; CGRect fileTextFieldFrame = CGRectMake(10, 15, 150, 25); UITextField *filePrompt = [

I'm trying to draw an image, with a source Bitmap and an alpha mask Bitmap , using the System.Drawing.Graphics object. At the moment I loop X and Y and use GetPixel and SetPixel to write the source color and mask alpha to a third Bitmap , and then render that. However this is very inefficient and I am wondering if there is an faster way to achieve this? The effect I'm after looks like this: The grid pattern represents transparency; you probably knew that. Yes, the faster way to do this is to use Bitmap.LockBits and use pointer arithmetic to retrieve the values instead of GetPixel and SetPixel