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Use optimized scrolling for all three scroll operations of FigureCanvas
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FigureCanvas' scrollToX and scrollToY uses an optimized scrolling
functionality which leads especially for views with many figures to a
much smoother scrolling experience.

This commit utilizes this optimized scrolling also for scrollTo.

Furthermore the code for all three has been combined in such a way that
all three use the same core functions.
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@azoitl
azoitl committed Mar 9, 2024
1 parent 64bd301 commit f1a6cc7
Showing 1 changed file with 36 additions and 61 deletions.
97 changes: 36 additions & 61 deletions org.eclipse.draw2d/src/org/eclipse/draw2d/FigureCanvas.java
View file
Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*******************************************************************************
* Copyright (c) 2000, 2023 IBM Corporation and others.
* Copyright (c) 2000, 2024 IBM Corporation and others.
*
* This program and the accompanying materials are made available under the
* terms of the Eclipse Public License 2.0 which is available at
Expand Down Expand Up @@ -189,10 +189,8 @@ private static int checkStyle(int style) {
*/
@Override
public org.eclipse.swt.graphics.Point computeSize(int wHint, int hHint, boolean changed) {
// TODO Still doesn't handle scrollbar cases, such as when a constrained
// width
// would require a horizontal scrollbar, and therefore additional
// height.
// TODO Still doesn't handle scrollbar cases, such as when a constrained width
// would require a horizontal scrollbar, and therefore additional height.
int borderSize = computeTrim(0, 0, 0, 0).x * -2;
if (wHint >= 0) {
wHint = Math.max(0, wHint - borderSize);
Expand Down Expand Up @@ -264,6 +262,7 @@ private void hook() {
getLightweightSystem().getUpdateManager().addUpdateListener(new UpdateListener() {
@Override
public void notifyPainting(Rectangle damage, java.util.Map<IFigure, Rectangle> dirtyRegions) {
// nothing to do for now
}

@Override
Expand Down Expand Up @@ -372,15 +371,9 @@ public void scrollSmoothTo(int x, int y) {
* @param y the y coordinate to scroll to
*/
public void scrollTo(int x, int y) {
x = verifyScrollBarOffset(getViewport().getHorizontalRangeModel(), x);
y = verifyScrollBarOffset(getViewport().getVerticalRangeModel(), y);
if (x == getViewport().getViewLocation().x) {
scrollToY(y);
} else if (y == getViewport().getViewLocation().y) {
scrollToX(x);
} else {
getViewport().setViewLocation(x, y);
}
int hOffset = verifyScrollBarOffset(getViewport().getHorizontalRangeModel(), x);
int vOffset = verifyScrollBarOffset(getViewport().getVerticalRangeModel(), y);
performScroll(hOffset, vOffset);
}

/**
Expand All @@ -395,44 +388,7 @@ public void scrollToX(int hOffset) {
if (hOffset == hOffsetOld) {
return;
}
int dx = -hOffset + hOffsetOld;

Rectangle clientArea = getViewport().getBounds().getShrinked(getViewport().getInsets());
Rectangle blit = clientArea.getResized(-Math.abs(dx), 0);
Rectangle expose = clientArea.getCopy();
Point dest = clientArea.getTopLeft();
expose.width = Math.abs(dx);
if (dx < 0) { // Moving left?
blit.translate(-dx, 0); // Move blit area to the right
expose.x = dest.x + blit.width;
} else {
// Moving right
dest.x += dx; // Move expose area to the right
}

// fix for bug 41111
Control[] children = getChildren();
boolean[] manualMove = new boolean[children.length];
for (int i = 0; i < children.length; i++) {
org.eclipse.swt.graphics.Rectangle bounds = children[i].getBounds();
manualMove[i] = blit.width <= 0 || bounds.x > blit.x + blit.width || bounds.y > blit.y + blit.height
|| bounds.x + bounds.width < blit.x || bounds.y + bounds.height < blit.y;
}
scroll(dest.x, dest.y, blit.x, blit.y, blit.width, blit.height, true);
for (int i = 0; i < children.length; i++) {
if (children[i].isDisposed()) {
continue;
}
org.eclipse.swt.graphics.Rectangle bounds = children[i].getBounds();
if (manualMove[i]) {
children[i].setBounds(bounds.x + dx, bounds.y, bounds.width, bounds.height);
}
}

getViewport().setIgnoreScroll(true);
getViewport().setHorizontalLocation(hOffset);
getViewport().setIgnoreScroll(false);
redraw(expose.x, expose.y, expose.width, expose.height, true);
performScroll(hOffset, getViewport().getViewLocation().y);
}

/**
Expand All @@ -447,12 +403,26 @@ public void scrollToY(int vOffset) {
if (vOffset == vOffsetOld) {
return;
}
int dy = -vOffset + vOffsetOld;
performScroll(getViewport().getViewLocation().x, vOffset);
}

private void performScroll(int hOffset, int vOffset) {
int dx = -hOffset + getViewport().getViewLocation().x;
int dy = -vOffset + getViewport().getViewLocation().y;
Rectangle clientArea = getViewport().getBounds().getShrinked(getViewport().getInsets());
Rectangle blit = clientArea.getResized(0, -Math.abs(dy));
Rectangle blit = clientArea.getResized(-Math.abs(dx), -Math.abs(dy));
Rectangle expose = clientArea.getCopy();
Point dest = clientArea.getTopLeft();

expose.width = Math.abs(dx);
if (dx < 0) { // Moving left?
blit.translate(-dx, 0); // Move blit area to the right
expose.x = dest.x + blit.width;
} else {
// Moving right
dest.x += dx; // Move expose area to the right
}

expose.height = Math.abs(dy);
if (dy < 0) { // Moving up?
blit.translate(0, -dy); // Move blit area down
Expand All @@ -462,12 +432,22 @@ public void scrollToY(int vOffset) {
dest.y += dy;
}

scrollChildren(dx, dy, blit, dest);

getViewport().setIgnoreScroll(true);
getViewport().setHorizontalLocation(hOffset);
getViewport().setVerticalLocation(vOffset);
getViewport().setIgnoreScroll(false);
redraw(expose.x, expose.y, expose.width, expose.height, true);
}

private void scrollChildren(int dx, int dy, Rectangle blit, Point dest) {
// fix for bug 41111
Control[] children = getChildren();
boolean[] manualMove = new boolean[children.length];
for (int i = 0; i < children.length; i++) {
org.eclipse.swt.graphics.Rectangle bounds = children[i].getBounds();
manualMove[i] = blit.height <= 0 || bounds.x > blit.x + blit.width || bounds.y > blit.y + blit.height
manualMove[i] = blit.width <= 0 || bounds.x > blit.x + blit.width || bounds.y > blit.y + blit.height
|| bounds.x + bounds.width < blit.x || bounds.y + bounds.height < blit.y;
}
scroll(dest.x, dest.y, blit.x, blit.y, blit.width, blit.height, true);
Expand All @@ -477,14 +457,9 @@ public void scrollToY(int vOffset) {
}
org.eclipse.swt.graphics.Rectangle bounds = children[i].getBounds();
if (manualMove[i]) {
children[i].setBounds(bounds.x, bounds.y + dy, bounds.width, bounds.height);
children[i].setBounds(bounds.x + dx, bounds.y + dy, bounds.width, bounds.height);
}
}

getViewport().setIgnoreScroll(true);
getViewport().setVerticalLocation(vOffset);
getViewport().setIgnoreScroll(false);
redraw(expose.x, expose.y, expose.width, expose.height, true);
}

/**
Expand Down

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