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[Win32] Reuse zoom handle for drawing image at size if appropriate #2634

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[Win32] Reuse zoom handle for drawing image at size if appropriate #2634

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84 changes: 47 additions & 37 deletions bundles/org.eclipse.swt/Eclipse SWT/win32/org/eclipse/swt/graphics/Image.java
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Original file line number Diff line number Diff line change
Expand Up @@ -141,33 +141,66 @@ public final class Image extends Resource implements Drawable {

private List<Consumer<Image>> onDisposeListeners;

private record CachedHandle(ImageHandle handleContainer, int requestedWidth, int requestedHeight) {
private class HandleAtSize {
private ImageHandle handleContainer = null;
private int requestedWidth = -1;
private int requestedHeight = -1;

public void destroy() {
if (handleContainer != null) {
if (handleContainer != null && !zoomLevelToImageHandle.containsValue(handleContainer)) {
handleContainer.destroy();
}
handleContainer = null;
requestedWidth = -1;
requestedHeight = -1;
}

public boolean isReusable(int height, int width) {
if(handleContainer == null) {
public ImageHandle refresh(int width, int height) {
if (!isReusable(width, height)) {
destroy();
requestedWidth = width;
requestedHeight = height;
handleContainer = createHandleAtExactSize(width, height)
.orElseGet(() -> getOrCreateImageHandleAtClosestSize(width, height));
}
return handleContainer;
}

private boolean isReusable(int width, int height) {
if (handleContainer == null) {
return false;
}
return (requestedHeight == height && requestedWidth == width)
|| (handleContainer.height == height && handleContainer.width == width);
}

private Optional<ImageHandle> createHandleAtExactSize(int widthHint, int heightHint) {
Optional<ImageData> imageData = imageProvider.loadImageDataAtExactSize(widthHint, heightHint);
if (imageData.isPresent()) {
ImageData adaptedData = adaptImageDataIfDisabledOrGray(imageData.get());
ImageHandle imageHandle = init(adaptedData, -1);
return Optional.of(imageHandle);
}
return Optional.empty();
}

public long getHandle() {
if (handleContainer != null) {
return handleContainer.handle;
private ImageHandle getOrCreateImageHandleAtClosestSize(int widthHint, int heightHint) {
Rectangle bounds = getBounds(100);
int imageZoomForWidth = 100 * widthHint / bounds.width;
int imageZoomForHeight = 100 * heightHint / bounds.height;
int imageZoom = DPIUtil.getZoomForAutoscaleProperty(Math.max(imageZoomForWidth, imageZoomForHeight));
ImageHandle bestFittingHandle = zoomLevelToImageHandle.get(imageZoom);
if (bestFittingHandle == null) {
ImageData bestFittingImageData = imageProvider.loadImageData(imageZoom).element();
ImageData adaptedData = adaptImageDataIfDisabledOrGray(bestFittingImageData);
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@arunjose696 arunjose696 Oct 20, 2025 •
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Doesnt the loadImageData(zoom) already do the adaptImageDataIfDisabledOrGray, so I think this is not needed.

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If I am not mistaken, adaptImageDataIfDisabledOrGray() is only called at places where a handle is created, such as initializeHandleFromSource(). None of the loadIamgeData() implementations seems to call it. Can you please check if I miss something, @arunjose696?

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I see the following call stack

loadImageData(int) -> getImageMetadata(zoomContext) -> newImageHandle(zoomContext)-> initializeHandleFromSource(zoomContext) -> adaptImageDataIfDisabledOrGray()

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I see. This seems to be an inconsistency that some loadImageData() implementations adapt the image data while others don't. Precisely, the PlainImageProviderWrapper and ExistingImageHandlerProviderWrapper seem to be the only ones that adapt them (via calling getClosedAvailableImageData()). We should try to streamline that (independent of this PR), as we unnecessarily adapt images twice (and maybe there are even some that we do not adapt at all).

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We should try to streamline that (independent of this PR), as we unnecessarily adapt images twice (and maybe there are even some that we do not adapt at all).

Yeah this could be streamlined in a seperate PR if running adaptImageDataIfDisabledOrGray is a no-op if applied for second time, I could see in addition to PlainImageProviderWrapper and ExistingImageHandlerProviderWrapper , the ImageGCDrawer wrapper also calls adaptImageDataIfDisabledOrGray

bestFittingHandle = init(adaptedData, -1);
}
return -1;
return bestFittingHandle;
}
};

// Initialize lastRequestedHandle with -1 for size-related fields to indicate uninitialized values
CachedHandle lastRequestedHandle = new CachedHandle(null, -1, -1);
}

private final HandleAtSize lastRequestedHandle = new HandleAtSize();

private Image (Device device, int type, long handle, int nativeZoom) {
super(device);
Expand Down Expand Up @@ -854,15 +887,8 @@ interface HandleAtSizeConsumer {
}

void executeOnImageHandleAtSize(HandleAtSizeConsumer handleAtSizeConsumer, int widthHint, int heightHint) {
if (!lastRequestedHandle.isReusable(heightHint, widthHint)) {
ImageData imageData;
imageData = this.imageProvider.loadImageDataAtSize(widthHint, heightHint);
lastRequestedHandle.destroy();
ImageHandle handleContainer = init(imageData, -1);
lastRequestedHandle = new CachedHandle(handleContainer, widthHint, heightHint);
}
handleAtSizeConsumer.accept(lastRequestedHandle.getHandle(),
new Point(lastRequestedHandle.handleContainer().width, lastRequestedHandle.handleContainer().height));
ImageHandle imageHandle = lastRequestedHandle.refresh(widthHint, heightHint);
handleAtSizeConsumer.accept(imageHandle.handle, new Point(imageHandle.width, imageHandle.height));
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Since we are now passing the imageHandle directly, the HandleAtSizeConsumer functional interface could be replaced with a standard Consumer<ImageHandle>, as all other arguments can be derived from the imageHandle itself.

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ImageHandle is private and I did not want to expose it just for this single case. If we merge #2651 soon (which will increase visibility of the ImageHandle class), I will adapt this accordingly.

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Makes sense

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I have created:

We should merge that one first, so I can adapt this on top of that refactoring.

}

/**
Expand Down Expand Up @@ -1096,8 +1122,8 @@ void destroy () {
}

private void destroyHandles() {
destroyHandles(__ -> true);
lastRequestedHandle.destroy();
destroyHandles(__ -> true);
}

@Override
Expand Down Expand Up @@ -2007,22 +2033,6 @@ ElementAtZoom<ImageData> getClosestAvailableImageData(int zoom) {
return new ElementAtZoom<>(getImageMetadata(new ZoomContext(closestZoom)).getImageData(), closestZoom);
}

public ImageData loadImageDataAtSize(int widthHint, int heightHint) {
Optional<ImageData> exact = loadImageDataAtExactSize(widthHint, heightHint);
if (exact.isPresent()) {
return adaptImageDataIfDisabledOrGray(exact.get());
}
return loadImageDataClosestTo(widthHint, heightHint);
}

private ImageData loadImageDataClosestTo(int targetWidth, int targetHeight) {
Rectangle bounds = getBounds(100);
int imageZoomForWidth = 100 * targetWidth / bounds.width;
int imageZoomForHeight = 100 * targetHeight / bounds.height;
int imageZoom = DPIUtil.getZoomForAutoscaleProperty(Math.max(imageZoomForWidth, imageZoomForHeight));
return loadImageData(imageZoom).element();
}

protected Optional<ImageData> loadImageDataAtExactSize(int width, int height) {
return Optional.empty(); // exact size not available
}
Expand Down
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