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Adapt double buffering use cases for multi-zoom
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This commit replaces three use cases where GC together with Images where
used to draw double buffered images. With new multi-zoom-setting in
Windows this leads to desctructive scaling and fragments caused by the
double buffering of Images/GCs created with different zoom. The changes
utilize the newly added ImageGcDrawer to provide a dynamic callback to
draw on a correctly initialized GC on demand.
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@akoch-yatta
akoch-yatta committed Jan 20, 2025
1 parent 8029b47 commit 15ecdb7
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Showing 3 changed files with 82 additions and 31 deletions.
24 changes: 19 additions & 5 deletions bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/source/AnnotationRulerColumn.java
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageGcDrawer;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Canvas;
Expand Down Expand Up @@ -266,6 +267,13 @@ public Control createControl(CompositeRuler parentRuler, Composite parentControl
fCachedTextWidget= null;
});

fCanvas.addListener(SWT.ZoomChanged, e -> {
if (fBuffer != null) {
fBuffer.dispose();
fBuffer= null;
}
});

fMouseListener= new MouseListener() {
@Override
public void mouseUp(MouseEvent event) {
Expand Down Expand Up @@ -517,10 +525,18 @@ private void doubleBufferPaint(GC dest) {
fBuffer= null;
}
}
if (fBuffer == null)
fBuffer= new Image(fCanvas.getDisplay(), size.x, size.y);
if (fBuffer == null) {
ImageGcDrawer imageGcDrawer= (gc, imageWidth, imageHeight) -> {
doPaint(gc, new Point(imageWidth, imageHeight));
};
fBuffer= new Image(fCanvas.getDisplay(), imageGcDrawer, size.x, size.y);
} else {
doPaint(new GC(fBuffer), size);
}
dest.drawImage(fBuffer, 0, 0);
}

GC gc= new GC(fBuffer);
private void doPaint(GC gc, Point size) {
gc.setFont(fCachedTextWidget.getFont());
try {
gc.setBackground(fCanvas.getBackground());
Expand All @@ -533,8 +549,6 @@ private void doubleBufferPaint(GC dest) {
} finally {
gc.dispose();
}

dest.drawImage(fBuffer, 0, 0);
}

/**
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41 changes: 28 additions & 13 deletions bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/source/ChangeRulerColumn.java
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageGcDrawer;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Canvas;
Expand Down Expand Up @@ -199,6 +200,13 @@ public Control createControl(CompositeRuler parentRuler, Composite parentControl
fCachedTextWidget= null;
});

fCanvas.addListener(SWT.ZoomChanged, e -> {
if (fBuffer != null) {
fBuffer.dispose();
fBuffer= null;
}
});

fCanvas.addMouseListener(fMouseHandler);
fCanvas.addMouseMoveListener(fMouseHandler);

Expand Down Expand Up @@ -249,19 +257,13 @@ private void doubleBufferPaint(GC dest) {
fBuffer= null;
}
}
if (fBuffer == null)
fBuffer= new Image(fCanvas.getDisplay(), size.x, size.y);

GC gc= new GC(fBuffer);
gc.setFont(fCanvas.getFont());

try {
gc.setBackground(getBackground());
gc.fillRectangle(0, 0, size.x, size.y);

doPaint(gc);
} finally {
gc.dispose();
if (fBuffer == null) {
ImageGcDrawer imageGcDrawer= (gc, imageWidth, imageHeight) -> {
doPaint(gc, new Point(imageWidth, imageHeight));
};
fBuffer= new Image(fCanvas.getDisplay(), imageGcDrawer, size.x, size.y);
} else {
doPaint(new GC(fBuffer), size);
}

dest.drawImage(fBuffer, 0, 0);
Expand Down Expand Up @@ -291,6 +293,19 @@ protected final boolean isViewerCompletelyShown() {
return JFaceTextUtil.isShowingEntireContents(fCachedTextWidget);
}

private void doPaint(GC gc, Point size) {
gc.setFont(fCanvas.getFont());

try {
gc.setBackground(getBackground());
gc.fillRectangle(0, 0, size.x, size.y);

doPaint(gc);
} finally {
gc.dispose();
}
}

/**
* Draws the ruler column.
*
Expand Down
48 changes: 35 additions & 13 deletions bundles/org.eclipse.jface.text/src/org/eclipse/jface/text/source/LineNumberRulerColumn.java
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Original file line number Diff line number Diff line change
Expand Up @@ -34,6 +34,7 @@
import org.eclipse.swt.graphics.FontMetrics;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.graphics.ImageGcDrawer;
import org.eclipse.swt.graphics.Point;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Canvas;
Expand Down Expand Up @@ -616,7 +617,13 @@ public void addMouseListener(MouseListener listener) {
fCachedTextWidget= null;
});

fCanvas.addListener(SWT.ZoomChanged, e -> computeIndentations());
fCanvas.addListener(SWT.ZoomChanged, e -> {
computeIndentations();
if (fBuffer != null) {
fBuffer.dispose();
fBuffer= null;
}
});

fMouseHandler= new MouseHandler();
fCanvas.addMouseListener(fMouseHandler);
Expand Down Expand Up @@ -681,8 +688,17 @@ private void doubleBufferPaint(GC dest) {

boolean bufferStillValid = fBuffer != null;
if (fBuffer == null) {
fBuffer= new Image(fCanvas.getDisplay(), size.x, size.y);
}
ImageGcDrawer imageGcDrawer= (gc, imageWidth, imageHeight) -> {
ILineRange lines= JFaceTextUtil.getVisibleModelLines(fCachedTextViewer);
if (lines == null) {
return;
}
// We redraw everything; paint directly into the buffer
initializeGC(gc, 0, 0, imageWidth, imageHeight);
doPaint(gc, lines);
};
fBuffer= new Image(fCanvas.getDisplay(), imageGcDrawer, size.x, size.y);
} else {
GC bufferGC= new GC(fBuffer);
Image newBuffer= null;
try {
Expand Down Expand Up @@ -745,16 +761,7 @@ private void doubleBufferPaint(GC dest) {
fLastBottomModelLine= bottomModelLine;
fLastHeight= height;
if (dy != 0) {
// Some rulers may paint outside the line region. Let them paint in a new image,
// the copy the wanted bits.
newBuffer= new Image(fCanvas.getDisplay(), size.x, size.y);
GC localGC= new GC(newBuffer);
try {
initializeGC(localGC, 0, bufferY, size.x, bufferH);
doPaint(localGC, visibleLines);
} finally {
localGC.dispose();
}
newBuffer= newBufferImage(size, bufferY, bufferH, visibleLines);
bufferGC.drawImage(newBuffer, 0, bufferY, size.x, bufferH, 0, bufferY, size.x, bufferH);
if (dy > 0 && bufferY + bufferH < size.y) {
// Scrolled down in the text, but didn't use the full height of the Canvas: clear
Expand All @@ -774,9 +781,24 @@ private void doubleBufferPaint(GC dest) {
newBuffer.dispose();
}
}
}
dest.drawImage(fBuffer, 0, 0);
}

private Image newBufferImage(Point size, int bufferY, int bufferH, final ILineRange visibleLines) {
ImageGcDrawer imageGcDrawer= (localGC, imageWidth, imageHeight) -> {
// Some rulers may paint outside the line region. Let them paint in a new image,
// the copy the wanted bits.
try {
initializeGC(localGC, 0, bufferY, imageWidth, bufferH);
doPaint(localGC, visibleLines);
} finally {
localGC.dispose();
}
};
return new Image(fCanvas.getDisplay(), imageGcDrawer, size.x, size.y);
}

private void initializeGC(GC gc, int x, int y, int width, int height) {
gc.setFont(fCanvas.getFont());
if (fForeground != null) {
Expand Down

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