Bitmaps, device dependent vs device independent, which is faster (or better)?
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I am working at blitting to back frame buffers a changing variety of bitmaps to create animations. When completed, that would be sent to the screen. I want to do this with minimum processing and minimum RAM. Svetoslav Chekanov, on another page Fast 2:1 Image Shrink (Scale Down)[^] said,
Quote:
Device dependent format is blitted faster to the screen.
I did not know that. I have been using Device Independent because it seemed to be easier to work with. I will now consider this Dependent vs Independent. I found a discussion with some interesting observations. C++ Windows API: Is there any alternative of the SetDIBits for device-dependent Bitmap?[^] In that I found:
Quote:
The difference is insignificant, more than swamped by the time it takes to copy the bitmap to the frame buffer.
May I have some feedback on this "is insignificant" comment (from the Windows API link) if it is correct or not? I also read on that page,
Quote:
In a DIB, each scanline is always a multiple of 4 bytes. In a 24-bit DIB, that means you will have extra padding bytes unless the width is a multiple of 4.
I did not know that. I will now have that to consider. Looking forward to learning more about this.
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I am working at blitting to back frame buffers a changing variety of bitmaps to create animations. When completed, that would be sent to the screen. I want to do this with minimum processing and minimum RAM. Svetoslav Chekanov, on another page Fast 2:1 Image Shrink (Scale Down)[^] said,
Quote:
Device dependent format is blitted faster to the screen.
I did not know that. I have been using Device Independent because it seemed to be easier to work with. I will now consider this Dependent vs Independent. I found a discussion with some interesting observations. C++ Windows API: Is there any alternative of the SetDIBits for device-dependent Bitmap?[^] In that I found:
Quote:
The difference is insignificant, more than swamped by the time it takes to copy the bitmap to the frame buffer.
May I have some feedback on this "is insignificant" comment (from the Windows API link) if it is correct or not? I also read on that page,
Quote:
In a DIB, each scanline is always a multiple of 4 bytes. In a 24-bit DIB, that means you will have extra padding bytes unless the width is a multiple of 4.
I did not know that. I will now have that to consider. Looking forward to learning more about this.
