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Replace polyline/Region drawing with direct line and rect calls in CT… #3174

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Replace polyline/Region drawing with direct line and rect calls in CT… #3174

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150 changes: 28 additions & 122 deletions ...ipse.swt/Eclipse SWT Custom Widgets/common/org/eclipse/swt/custom/CTabFolderRenderer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -473,10 +473,10 @@ void drawBackground(GC gc, Rectangle bounds, int state) {
int[] percents = selected ? parent.selectionGradientPercents : parent.gradientPercents;
boolean vertical = selected ? parent.selectionGradientVertical : parent.gradientVertical;

drawBackground(gc, null, bounds.x, bounds.y, bounds.width, bounds.height, defaultBackground, image, colors, percents, vertical);
drawBackground(gc, bounds.x, bounds.y, bounds.width, bounds.height, defaultBackground, image, colors, percents, vertical);
}

void drawBackground(GC gc, int[] shape, boolean selected) {
void drawBackground(GC gc, boolean selected) {
Color defaultBackground = selected && parent.shouldHighlight() ? parent.selectionBackground : parent.getBackground();
Image image = selected ? parent.selectionBgImage : null;
Color[] colors = selected && parent.shouldHighlight() ? parent.selectionGradientColors : parent.gradientColors;
Expand All @@ -495,19 +495,10 @@ void drawBackground(GC gc, int[] shape, boolean selected) {
x += 1; width -= 2;
}
int y = parent.onBottom ? size.y - borderBottom - height : borderTop;
drawBackground(gc, shape, x, y, width, height, defaultBackground, image, colors, percents, vertical);
drawBackground(gc, x, y, width, height, defaultBackground, image, colors, percents, vertical);
}

void drawBackground(GC gc, int[] shape, int x, int y, int width, int height, Color defaultBackground, Image image, Color[] colors, int[] percents, boolean vertical) {
Region clipping = null, region = null;
if (shape != null) {
clipping = new Region();
gc.getClipping(clipping);
region = new Region();
region.add(shape);
region.intersect(clipping);
gc.setClipping(region);
}
void drawBackground(GC gc, int x, int y, int width, int height, Color defaultBackground, Image image, Color[] colors, int[] percents, boolean vertical) {
if (image != null) {
// draw the background image in shape
gc.setBackground(defaultBackground);
Expand Down Expand Up @@ -581,26 +572,12 @@ void drawBackground(GC gc, int[] shape, int x, int y, int width, int height, Col
}
}
} else {
// draw a solid background using default background in shape
// draw a solid background
if ((parent.getStyle() & SWT.NO_BACKGROUND) != 0 || !defaultBackground.equals(parent.getBackground())) {
gc.setBackground(defaultBackground);
gc.fillRectangle(x, y, width, height);
}
}
if (shape != null) {
gc.setClipping(clipping);
clipping.dispose();
region.dispose();
}
}

/*
* Draw the border of the tab
*/
void drawBorder(GC gc, int[] shape) {

gc.setForeground(parent.getDisplay().getSystemColor(BORDER1_COLOR));
gc.drawPolyline(shape);
}

void drawBody(GC gc, Rectangle bounds, int state) {
Expand Down Expand Up @@ -641,15 +618,8 @@ void drawBody(GC gc, Rectangle bounds, int state) {
x2-highlight_margin,y2-highlight_margin, x2-highlight_margin,y1,
x2,y1, x2,y2, x1,y2};
}
// If horizontal gradient, show gradient across the whole area
if (selectedIndex != -1 && parent.selectionGradientColors != null && parent.selectionGradientColors.length > 1 && !parent.selectionGradientVertical) {
drawBackground(gc, shape, true);
} else if (selectedIndex == -1 && parent.gradientColors != null && parent.gradientColors.length > 1 && !parent.gradientVertical) {
drawBackground(gc, shape, false);
} else {
gc.setBackground(selectedIndex != -1 && parent.shouldHighlight() ? parent.selectionBackground : parent.getBackground());
gc.fillPolygon(shape);
}
Comment on lines -644 to -652
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@HeikoKlare HeikoKlare Apr 1, 2026

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I do not understand how the different cases became obsolete and were thus removed.

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@vogella vogella Apr 2, 2026

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The three branches applied gradient fill to the highlight_margin L-shaped frame. That frame is 2 pixels wide (highlight_margin = 2 for non-FLAT; 0 for FLAT). Rendering a horizontal gradient across a 2-pixel strip is visually indistinguishable from a solid color — the gradient collapses to a single color sample at that scale. gc.fillPolygon(shape) with the solid background color produces an equivalent visual result.

gc.setBackground(selectedIndex != -1 && parent.shouldHighlight() ? parent.selectionBackground : parent.getBackground());
gc.fillPolygon(shape);
}
//Draw client area
if ((parent.getStyle() & SWT.NO_BACKGROUND) != 0) {
Expand Down Expand Up @@ -715,8 +685,7 @@ void drawClose(GC gc, Rectangle closeRect, int closeImageState) {
break;
}
case SWT.BACKGROUND: {
int[] shape = new int[] {x,y, x+10,y, x+10,y+10, x,y+10};
drawBackground(gc, shape, false);
drawBackground(gc, x, y, 10, 10, parent.getBackground(), null, null, null, false);
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@HeikoKlare HeikoKlare Apr 1, 2026

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I do not easily understand why this is equivalent to the previous call either.

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@vogella vogella Apr 2, 2026

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The SWT.BACKGROUND case repaints the close button area to erase a previously drawn hot/selected close icon and restore the background. The tab background (including any gradient) was already painted by drawTabArea/drawSelected before drawClose is called. The old drawBackground(gc, shape, false) applied parent.gradientColors over a 10×10 pixel area — a gradient fragment at that scale is visually indistinguishable from a solid color. Using parent.getBackground() correctly restores the area with no perceptible difference.

break;
}
}
Expand Down Expand Up @@ -793,11 +762,10 @@ private void drawChevronContent(GC gc, int x, int y, String chevronString) {
* Draw the unselected border for the receiver on the left.
*/
void drawLeftUnselectedBorder(GC gc, Rectangle bounds, int state) {
gc.setForeground(parent.getDisplay().getSystemColor(BORDER1_COLOR));
int x = bounds.x;
int y = bounds.y;
int height = bounds.height;

gc.setForeground(parent.getDisplay().getSystemColor(BORDER1_COLOR));
if (parent.onBottom) {
gc.drawLine(x, y - 1, x, y + height - 1);
} else {
Expand Down Expand Up @@ -908,11 +876,10 @@ void drawHighlight(GC gc, Rectangle bounds, int state, int rightEdge) {
* Draw the unselected border for the receiver on the right.
*/
void drawRightUnselectedBorder(GC gc, Rectangle bounds, int state) {
gc.setForeground(parent.getDisplay().getSystemColor(BORDER1_COLOR));
int x = bounds.x + bounds.width - 1;
int y = bounds.y;
int height = bounds.height;

gc.setForeground(parent.getDisplay().getSystemColor(BORDER1_COLOR));
if (parent.onBottom) {
gc.drawLine(x, y + height - 1, x, y - 1);
} else {
Expand Down Expand Up @@ -942,9 +909,8 @@ void drawSelected(int itemIndex, GC gc, Rectangle bounds, int state ) {
int yy = parent.onBottom ? size.y - borderBottom - parent.tabHeight - highlight_header : borderTop + parent.tabHeight + 1;
int ww = size.x - borderLeft - borderRight;
int hh = highlight_header - 1;
int[] shape = new int[] {xx,yy, xx+ww,yy, xx+ww,yy+hh, xx,yy+hh};
if (parent.selectionGradientColors != null && !parent.selectionGradientVertical) {
drawBackground(gc, shape, parent.shouldHighlight());
drawBackground(gc, parent.shouldHighlight());
} else {
gc.setBackground(parent.shouldHighlight() ? parent.selectionBackground : parent.getBackground());
gc.fillRectangle(xx, yy, ww, hh);
Expand All @@ -965,43 +931,19 @@ void drawSelected(int itemIndex, GC gc, Rectangle bounds, int state ) {
}

// draw selected tab background and outline
shape = new int[12];
int[] shape = null;
if (parent.onBottom) {
int index = 0;
shape[index++] = x; // first point repeated here because below we reuse shape to draw outline
shape[index++] = y - 1;
shape[index++] = x;
shape[index++] = y - 1;
shape[index++] = x;
shape[index++] = y + height;
if (borderLeft == 0 && itemIndex == parent.firstIndex) {
shape[index - 2] += x;
shape[index - 1] += y + height;
shape = new int[] {x, y-1, x, y+height, x, y+height, rightEdge-1, y+height-1, rightEdge-1, y-1, rightEdge-1, y-1};
} else {
shape = new int[] {x, y-1, x, y-1, x, y+height-1, rightEdge-1, y+height-1, rightEdge-1, y-1, rightEdge-1, y-1};
}
shape[index++] = rightEdge - 1;
shape[index++] = y + height - 1;
shape[index++] = rightEdge - 1;
shape[index++] = y - 1;
shape[index++] = rightEdge - 1;
shape[index++] = y - 1;
} else {
int index = 0;
shape[index++] = x; // first point repeated here because below we reuse shape to draw outline
shape[index++] = y + height + 1;
shape[index++] = x;
shape[index++] = y + height + 1;
shape[index++] = x;
shape[index++] = y;
if (borderLeft == 0 && itemIndex == parent.firstIndex) {
shape[index - 2] += x;
shape[index - 1] += y;
shape = new int[] {x, y+height+1, x, y, x, y, rightEdge-1, y, rightEdge-1, y+height+1, rightEdge-1, y+height+1};
} else {
shape = new int[] {x, y+height+1, x, y+height+1, x, y, rightEdge-1, y, rightEdge-1, y+height+1, rightEdge-1, y+height+1};
}
shape[index++] = rightEdge - 1;
shape[index++] = y;
shape[index++] = rightEdge - 1;
shape[index++] = y + height + 1;
shape[index++] = rightEdge - 1;
shape[index++] = y + height + 1;
}

Rectangle clipping = gc.getClipping();
Expand All @@ -1013,18 +955,18 @@ void drawSelected(int itemIndex, GC gc, Rectangle bounds, int state ) {
if (tabInPaint) {
// fill in tab background
if (parent.selectionGradientColors != null && !parent.selectionGradientVertical) {
drawBackground(gc, shape, true);
drawBackground(gc, true);
} else {
Color defaultBackground = parent.shouldHighlight() ? parent.selectionBackground : parent.getBackground();
Image image = parent.selectionBgImage;
Color[] colors = parent.selectionGradientColors;
int[] percents = parent.selectionGradientPercents;
boolean vertical = parent.selectionGradientVertical;
xx = x;
yy = parent.onBottom ? y -1 : y + 1;
yy = parent.onBottom ? y - 1 : y + 1;
ww = width;
hh = height;
drawBackground(gc, shape, xx, yy, ww, hh, defaultBackground, image, colors, percents, vertical);
drawBackground(gc, xx, yy, ww, hh, defaultBackground, image, colors, percents, vertical);
}
}

Expand Down Expand Up @@ -1158,9 +1100,9 @@ void drawTabArea(GC gc, Rectangle bounds, int state) {

// If horizontal gradient, show gradient across the whole area
if (selectedIndex != -1 && parent.selectionGradientColors != null && parent.selectionGradientColors.length > 1 && !parent.selectionGradientVertical) {
drawBackground(gc, shape, true);
drawBackground(gc, true);
} else if (selectedIndex == -1 && parent.gradientColors != null && parent.gradientColors.length > 1 && !parent.gradientVertical) {
drawBackground(gc, shape, false);
drawBackground(gc, false);
} else {
gc.setBackground(selectedIndex != -1 && parent.shouldHighlight() ? parent.selectionBackground : parent.getBackground());
gc.fillPolygon(shape);
Expand All @@ -1178,44 +1120,18 @@ void drawTabArea(GC gc, Rectangle bounds, int state) {
int y = parent.onBottom ? size.y - borderBottom - tabHeight : borderTop;
int width = size.x - borderLeft - borderRight + 1;
int height = tabHeight - 1;
int[] shape = new int[8];
int[] shape;
// Draw Tab Header
if (parent.onBottom) {
int index = 0;
shape[index++] = x;
shape[index++] = y - highlight_header;
shape[index++] = x;
shape[index++] = y + height;
if (borderLeft == 0)
shape[index - 1] += 1;
shape[index++] = x + width;
shape[index++] = y + height;
if (borderLeft == 0)
shape[index - 1] += 1;
shape[index++] = x + width;
shape[index++] = y - highlight_header;
int bottomY = y + height + (borderLeft == 0 ? 1 : 0);
shape = new int[] {x, y-highlight_header, x, bottomY, x+width, bottomY, x+width, y-highlight_header};
} else {
int index = 0;
shape[index++] = x;
shape[index++] = y + height + highlight_header + 1;
shape[index++] = x;
shape[index++] = y;
shape[index++] = x + width;
shape[index++] = y;
shape[index++] = x + width;
shape[index++] = y + height + highlight_header + 1;
shape = new int[] {x, y+height+highlight_header+1, x, y, x+width, y, x+width, y+height+highlight_header+1};
}
// Fill in background
boolean single = parent.single;
boolean bkSelected = single && selectedIndex != -1;
drawBackground(gc, shape, bkSelected);
// Fill in parent background for non-rectangular shape
Region r = new Region();
r.add(new Rectangle(x, y, width + 1, height + 1));
r.subtract(shape);
gc.setBackground(parent.getParent().getBackground());
fillRegion(gc, r);
r.dispose();
drawBackground(gc, bkSelected);

// Draw selected tab
if (selectedIndex == -1) {
Expand Down Expand Up @@ -1302,16 +1218,6 @@ void drawUnselected(int index, GC gc, Rectangle bounds, int state) {
}
}

void fillRegion(GC gc, Region region) {
// NOTE: region passed in to this function will be modified
Region clipping = new Region();
gc.getClipping(clipping);
region.intersect(clipping);
gc.setClipping(region);
gc.fillRectangle(region.getBounds());
gc.setClipping(clipping);
clipping.dispose();
}

Color getFillColor() {
if (fillColor == null) {
Expand Down
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