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Fix GC#drawImage methods with additional Transformation #2934

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Merged
HeikoKlare merged 1 commit into from
Jan 21, 2026
+31 −11
Merged

Fix GC#drawImage methods with additional Transformation #2934

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42 changes: 31 additions & 11 deletions bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/GC.java
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Original file line number Diff line number Diff line change
Expand Up @@ -521,6 +521,20 @@ void disposeAll() {
image.removeOnDisposeListener(disposeCallback);
super.disposeAll();
}

protected float calculateTransformationScale() {
Transform current = new Transform(device);
getTransform(current);
float[] m = new float[6];
current.getElements(m);
// this calculates the effective length in x and y
// direction without being affected by the rotation
// of the transformation
float scaleWidth = (float) Math.hypot(m[0], m[2]);
float scaleHeight = (float) Math.hypot(m[1], m[3]);
current.dispose();
return Math.max(scaleWidth, scaleHeight);
}
}

private class CopyAreaToImageOperation extends ImageOperation {
Expand Down Expand Up @@ -1181,11 +1195,13 @@ void apply() {
private void draw(Image image, int srcX, int srcY, int srcWidth, int srcHeight, int destX, int destY, int destWidth, int destHeight) {
int gcZoom = getZoom();
int requestedImageZoom = calculateZoomForImage(gcZoom, source.width, source.height, destination.width, destination.height);
float transformationScale = calculateTransformationScale();
int scaledImageZoomWithTransform = Math.round(transformationScale * requestedImageZoom);

Rectangle src = new Rectangle(srcX, srcY, srcWidth, srcHeight);
Rectangle destPixels = Win32DPIUtils.pointToPixel(drawable, new Rectangle(destX, destY, destWidth, destHeight), gcZoom);
Rectangle fullImageBounds = image.getBounds();
Rectangle requestedFullImageBoundsPixels = Win32DPIUtils.pointToPixel(drawable, fullImageBounds, requestedImageZoom);
Rectangle requestedFullImageBoundsPixels = Win32DPIUtils.pointToPixel(drawable, fullImageBounds, scaledImageZoomWithTransform);

image.executeOnImageHandleAtBestFittingSize((tempHandle) -> {
Rectangle srcPixels = computeSourceRectangle(tempHandle, fullImageBounds, src);
Expand Down Expand Up @@ -1252,18 +1268,22 @@ private class DrawScaledImageOperation extends ImageOperation {

@Override
void apply() {
int gcZoom = getZoom();
drawImage(getImage(), destination.x, destination.y, destination.width, destination.height, gcZoom);
draw(getImage(), destination.x, destination.y, destination.width, destination.height);
}
}

private void drawImage(Image image, int destX, int destY, int destWidth, int destHeight, int imageZoom) {
Rectangle destPixels = Win32DPIUtils.pointToPixel(drawable, new Rectangle(destX, destY, destWidth, destHeight),
imageZoom);
image.executeOnImageHandleAtBestFittingSize(tempHandle -> {
drawImage(image, 0, 0, tempHandle.width(), tempHandle.height(), destPixels.x, destPixels.y,
destPixels.width, destPixels.height, false, tempHandle);
}, destPixels.width, destPixels.height);
private void draw(Image image, int destX, int destY, int destWidth, int destHeight) {
int gcZoom = getZoom();
float transformationScale = calculateTransformationScale();
int scaledImageZoomWithTransform = Math.round(transformationScale * gcZoom);
Rectangle destPixels = Win32DPIUtils.pointToPixel(drawable, new Rectangle(destX , destY, destWidth , destHeight), gcZoom);
Rectangle destPixelsScaledWithTransform = Win32DPIUtils.pointToPixel(drawable, new Rectangle(destX , destY, destWidth , destHeight),
scaledImageZoomWithTransform);

image.executeOnImageHandleAtBestFittingSize(tempHandle -> {
drawImage(image, 0, 0, tempHandle.width(), tempHandle.height(), destPixels.x, destPixels.y,
destPixels.width, destPixels.height, false, tempHandle);
}, destPixelsScaledWithTransform.width, destPixelsScaledWithTransform.height);
}
}

private class DrawImageToImageOperation extends ImageOperation {
Expand Down
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