diff options
Diffstat (limited to 'libjava/classpath/javax/swing/JViewport.java')
| -rw-r--r-- | libjava/classpath/javax/swing/JViewport.java | 104 |
1 files changed, 78 insertions, 26 deletions
diff --git a/libjava/classpath/javax/swing/JViewport.java b/libjava/classpath/javax/swing/JViewport.java index debb5742e2c..2b5d1cd5a2f 100644 --- a/libjava/classpath/javax/swing/JViewport.java +++ b/libjava/classpath/javax/swing/JViewport.java @@ -48,6 +48,7 @@ import java.awt.Insets; import java.awt.LayoutManager; import java.awt.Point; import java.awt.Rectangle; +import java.awt.Shape; import java.awt.event.ComponentAdapter; import java.awt.event.ComponentEvent; import java.io.Serializable; @@ -113,7 +114,7 @@ public class JViewport extends JComponent implements Accessible /** * Creates a new instance of <code>AccessibleJViewport</code>. */ - public AccessibleJViewport() + protected AccessibleJViewport() { // Nothing to do here. } @@ -252,6 +253,13 @@ public class JViewport extends JComponent implements Accessible boolean sizeChanged = true; /** + * Indicates if this JViewport is the paint root or not. If it is not, then + * we may not assume that the offscreen buffer still has the right content + * because parent components may have cleared the background already. + */ + private boolean isPaintRoot = false; + + /** * Initializes the default setting for the scrollMode property. */ static @@ -635,11 +643,19 @@ public class JViewport extends JComponent implements Accessible */ public void repaint(long tm, int x, int y, int w, int h) { - Component parent = getParent(); - if (parent != null) - { - parent.repaint(tm, x + getX(), y + getY(), w, h); - } +// Component parent = getParent(); +// if (parent != null) +// parent.repaint(tm, x + getX(), y + getY(), w, h); +// else +// super.repaint(tm, x, y, w, h); + + // The specs suggest to implement something like the above. This however + // breaks blit painting, because the parent (most likely a JScrollPane) + // clears the background of the offscreen area of the JViewport, thus + // destroying the pieces that we want to clip. So we simply call super here + // instead. + super.repaint(tm, x, y, w, h); + } protected void addImpl(Component comp, Object constraints, int index) @@ -710,9 +726,11 @@ public class JViewport extends JComponent implements Accessible protected boolean computeBlit(int dx, int dy, Point blitFrom, Point blitTo, Dimension blitSize, Rectangle blitPaint) { - if ((dx != 0 && dy != 0) || damaged) + if ((dx != 0 && dy != 0) || (dy == 0 && dy == 0) || damaged) // We cannot blit if the viewport is scrolled in both directions at - // once. + // once. Also, we do not want to blit if the viewport is not scrolled at + // all, because that probably means the view component repaints itself + // and the buffer needs updating. return false; Rectangle portBounds = SwingUtilities.calculateInnerArea(this, getBounds()); @@ -791,6 +809,8 @@ public class JViewport extends JComponent implements Accessible Point pos = getViewPosition(); Component view = getView(); + Shape oldClip = g.getClip(); + g.clipRect(0, 0, getWidth(), getHeight()); boolean translated = false; try { @@ -802,6 +822,7 @@ public class JViewport extends JComponent implements Accessible { if (translated) g.translate (pos.x, pos.y); + g.setClip(oldClip); } } @@ -854,6 +875,11 @@ public class JViewport extends JComponent implements Accessible // everything. else { + // If the image has not been scrolled at all, only the changed + // clip must be updated in the buffer. + if (dx==0 && dy==0) + g2.setClip(g.getClip()); + paintSimple(g2); } g2.dispose(); @@ -877,23 +903,49 @@ public class JViewport extends JComponent implements Accessible */ void paintBlit(Graphics g) { - // We cannot perform blitted painting as it is described in Sun's API docs. - // There it is suggested that this painting method should blit directly - // on the parent window's surface. This is not possible because when using - // Swing's double buffering (at least our implementation), it would - // immediatly be painted when the buffer is painted on the screen. For this - // to work we would need a kind of hole in the buffer image. And honestly - // I find this method not very elegant. - // The alternative, blitting directly on the buffer image, is also not - // possible because the buffer image gets cleared everytime when an opaque - // parent component is drawn on it. - - // What we do instead is falling back to the backing store approach which - // is in fact a mixed blitting/backing store approach where the blitting - // is performed on the backing store image and this is then drawn to the - // graphics context. This is very robust and works independent of the - // painting mechanism that is used by Swing. And it should have comparable - // performance characteristics as the blitting method. - paintBackingStore(g); + // First we move the part that remains visible after scrolling, then + // we only need to paint the bit that becomes newly visible. + Point viewPosition = getViewPosition(); + int dx = viewPosition.x - lastPaintPosition.x; + int dy = viewPosition.y - lastPaintPosition.y; + boolean canBlit = computeBlit(dx, dy, cachedBlitFrom, cachedBlitTo, + cachedBlitSize, cachedBlitPaint); + if (canBlit && isPaintRoot) + { + // Copy the part that remains visible during scrolling. + g.copyArea(cachedBlitFrom.x, cachedBlitFrom.y, + cachedBlitSize.width, cachedBlitSize.height, + cachedBlitTo.x - cachedBlitFrom.x, + cachedBlitTo.y - cachedBlitFrom.y); + // Now paint the part that becomes newly visible. + Shape oldClip = g.getClip(); + g.clipRect(cachedBlitPaint.x, cachedBlitPaint.y, + cachedBlitPaint.width, cachedBlitPaint.height); + try + { + paintSimple(g); + } + finally + { + g.setClip(oldClip); + } + } + // If blitting is not possible for some reason, fall back to repainting + // everything. + else + paintSimple(g); + lastPaintPosition.setLocation(getViewPosition()); + } + + /** + * Overridden from JComponent to set the {@link #isPaintRoot} flag. + * + * @param r the rectangle to paint + */ + void paintImmediately2(Rectangle r) + { + isPaintRoot = true; + super.paintImmediately2(r); + isPaintRoot = false; } } |