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| -rw-r--r-- | areaplan.md | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/areaplan.md b/areaplan.md index 0a307c4..8c25ef6 100644 --- a/areaplan.md +++ b/areaplan.md @@ -88,7 +88,7 @@ GpStatus WINGDIPAPI GdipDrawImageI(GpGraphics *graphics, GpImage *image, INT x, GpStatus WINGDIPAPI GdipDeleteGraphics(GpGraphics *graphics); GpStatus WINGDIPAPI GdipDisposeImage(GpImage *image); ``` -(`GpBitmap` extends `GpImage`.) The only problem is the pixel format: the most appropriate one is `PixelFormat32bppARGB`, which is not premultiplied, but the components are in the wrong order... (there is no RGBA pixel format in any bit width) (TODO `GdipDisposeImage` seems wrong since it bypasses `~Bitmap()` and goes right for `~Image()` but I don't see an explicit `~Bitmap()`...) +(`GpBitmap` extends `GpImage`.) The only problem is the pixel format: the most appropriate one is `PixelFormat32bppARGB`, which is not premultiplied, but the components are in the wrong order... (specifically in BGRA order) (there is no RGBA pixel format in any bit width) (TODO `GdipDisposeImage` seems wrong since it bypasses `~Bitmap()` and goes right for `~Image()` but I don't see an explicit `~Bitmap()`...) Disregarding the RGBA issue, the draw code would be ```go @@ -122,6 +122,33 @@ Disregarding the RGBA issue, the draw code would be } ``` +Upon further review, there really doesn't seem to be any way around it: we have to shuffle the image data around. We seem to be in good company: [go.wde needs to do so as well](https://github.com/skelterjohn/go.wde/blob/master/win/dib_windows.go). But you can't be too sure... +```go + realbits := make([]byte, 4 * i.Rect.Dx() * I.Rect.Dy()) + q := 0 + for y := i.Rect.Min.Y; y < i.Rect.Max.Y; y++ { + k := i.Pix[y * i.Stride:] + for x := i.Rect.Min.X; x < i.Rect.Max.X; x += 4 { + realbits[q + 0] = byte(k[y + x + 2]) // B + realbits[q + 1] = byte(k[y + x + 1]) // G + realbits[q + 2] = byte(k[y + x + 0]) // R + realbits[q + 3] = byte(k[y + x + 3]) // A + q += 4 + } + } + + var bitmap, graphics uintptr + + status := GdipCreateBitmapFromScan0( + i.Rect.Dx(), + i.Rect.Dy(), + 0, // no stride anymore + PixelFormat32bppARGB, + &realbits[0], + &bitmap) + // rest of code +``` + We must also initialize and shut down GDI+ in uitask: ```go var ( |