Rendering bug with BLContext for certain image sizes about blend2d HOT 2 CLOSED

The following code is not correct:

pxs[y * width + x] = v.value;

To calculate a valid pixel address, use stride:

uint8_t* pxs = static_cast<uint8_t*>(data.pixelData);

for (const int y : range(height)) {
  uint32_t* scanline = reinterpret_cast<uint32_t*>(pxs);
  for (const int x : range(width)) {
    const BLRgba32 v = /* implementation details */;
    scanline[x] = v.value;
  }
  pxs += data.stride;
}

Blend2D would align large images to 4 pixels to maintain 16-byte alignment for each scanline. It would not align small images to not waste memory. Also, you can create subimages that have much larger stride than width, etc... So the only correct calculation is to use stride.

from blend2d.

Oh okay that makes sense, thank you! I was making the same mistake when generating an OpenGL texture from a BLImage, which is why the image rendered via BLContext looked weird. All works as expected now when using stride.

from blend2d.