rgba

Let's say I have this: .example { background-color: rgba(0, 0, 0, 0.5); border-color: rgba(0, 0, 0, 0.5); } The background-color and border-color have the same rgba value, but are different colors because the border-color is calculated on top of the background-color. (simple example: http://jsfiddle.net/BBdB3/ ) What transparency value for the border-color would make it match the background-color? What's the math here? Edit: thanks guys, using rgba(0, 0, 0, 0) or transparency is sufficient for my first example, but I still have a problem. ( http://jsfiddle.net/CPK7L/2/ ). In this case I need

The title looks a bit weird, so here is a sample: You will probably be familiar with the Windows 7 Explorer. When you select something with the pressed left mouse button, you get a blue half transparent rectangle. So the question is now: It is possible to calculate the source RGBA color that was used to draw this rectangle? The only things I know is the RGB value from the background and the RGB value with the blue overlay. Here is a screenshot from what I mean: No, it ist not possible from a single image. You need the target data over a black and a white image (best case). After that, you need

I've a simple question: If I'm not going to use Alpha on RGBA, for some colors, should I use HEX on these colors? Is there something HEX has that RGBA doesn't? Like browser compatibility, for example? Or is it just fine to use RGBA all the time? I find it better, cause if I would want to use Alpha, I could. Thanks in advance. Both should be compatible with any standards-compliant browser. Edit: There might be some buggy behavior in IE (suprise!): http://css-tricks.com/ie-background-rgb-bug/ When using RGBA, I believe the correct syntax is to use R, G, B values. Hence the name. I've not tried

As the title said, anyone know what is RGBX_8888 pixel format? and what is the difference with RGBA_8888? Is RGBA_8888 offers an alpha channel but RGBX_8888 does not? The android documentation does not give much information on this unfortunately. Thanks. RGBX means, that the pixel format still has an alpha channel, but it is ignored, and is always set to 255. Some reference: Blackberry PixelFormat (It is not android, however I guess that the naming conventions stay same across platforms.) The RGBX 32 bit RGB format is stored in memory as 8 red bits, 8 green bits, 8 blue bits, and 8 ignored

I'm trying to create a bitmap in memory as part of a pattern function that a drawLayer:inContext: method (this method is part of the CALayer delegate protocol) will call. The pattern function looks similar to this: static const size_t kComponentsPerPixel = 4; static const size_t kBitsPerComponent = sizeof(unsigned char) * 8; NSInteger layerHeight = 160; NSInteger layerWidth = 160; CGContextSaveGState(context); CGColorSpaceRef rgb = CGColorSpaceCreateDeviceRGB(); size_t bufferLength = layerWidth * layerHeight * kComponentsPerPixel; unsigned char *buffer = malloc(bufferLength); // The real

I have the source code for a video decoder application written in C, which I'm now porting on iphone. My problem is as follows: I have RGBA pixel data for a frame in a buffer that I need to display on the screen. My buffer is of type unsigned char. (I cannot change it to any other data type as the source code is too huge and not written by me.) Most of the links I found on the net say about how to "draw and display pixels" on the screen or how to "display pixels present in an array", but none of then say how to "display pixel data present in a buffer". I'm planning to use quartz 2D. All I need