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At 100% zoom: kpMainWindow::drawTransparentBackground() accounts for
about 75% of kpView::paintEvent()'s time. Bottleneck is
QPainter::fillRect(). QPainter::drawPixmap() seems much faster. For
800x600, renderer goes from 10ms to 1ms.
2007-10-12:
Have not reprofiled KolourPaint under Qt4 to determine whether this patch
is still worthwhile (I suspect it still is since QPainter/X11 could not
magically have gotten faster). In any case, the patch needs to be updated
before being applied.
--- kpmainwindow.cpp 2004-08-05 02:10:38.000000000 +1000
+++ kpmainwindow.cpp 2004-09-29 11:24:45.000000000 +1000
@@ -838,12 +838,116 @@
}
+#if 1
+// (indexed by [isPreview][parity])
+static QPixmap *checkerBoardCache [2][2] = {{0, 0}, {0, 0}};
+
+
+static int checkerBoardCellSize (bool isPreview)
+{
+ return !isPreview ? 16 : 10;
+}
+
+
+// public
+static QPixmap *createCheckerBoardCache (bool isPreview, bool parity)
+{
+ int cellSize = checkerBoardCellSize (isPreview);
+ const int rep = 2; // must be multiple of 2
+
+ QPixmap *newPixmap = new QPixmap (cellSize * rep, cellSize * rep);
+ QPainter painter (newPixmap);
+
+ int parityAsInt = parity ? 1 : 0;
+ for (int y = 0; y < rep; y++)
+ {
+ for (int x = 0; x < rep; x++)
+ {
+ QColor col;
+
+ if ((parityAsInt + x + y) % 2)
+ {
+ if (!isPreview)
+ col = QColor (213, 213, 213);
+ else
+ col = QColor (224, 224, 224);
+ }
+ else
+ col = Qt::white;
+
+ painter.fillRect (x * cellSize, y * cellSize,
+ cellSize, cellSize,
+ col);
+ }
+ }
+
+ painter.end ();
+ return newPixmap;
+}
+
+void kpMainWindow::drawTransparentBackground (QPainter *painter,
+ int /*viewWidth*/, int /*viewHeight*/,
+ const QRect &rect,
+ bool isPreview)
+{
+#if DEBUG_KP_MAIN_WINDOW && 1 || 1
+ kDebug () << "\tkpMainWindow::drawTransparentBackground(rect="
+ << rect << ")" << endl;
+ QTime totalTimer; totalTimer.start ();
+#endif
+
+ int cellSize = checkerBoardCellSize (isPreview);
+
+
+ int starty = rect.y ();
+ if (starty % cellSize)
+ starty -= (starty % cellSize);
+
+ int startx = rect.x ();
+ if (startx % cellSize)
+ startx -= (startx % cellSize);
+
+
+ int parity = ((startx / cellSize + starty / cellSize) % 2) ? 1 : 0;
+
+ if (!checkerBoardCache [isPreview][parity])
+ {
+ checkerBoardCache [isPreview][parity] = createCheckerBoardCache (isPreview, parity);
+ }
+
+ QPixmap *tilePixmap = checkerBoardCache [isPreview][parity];
+ for (int y = starty; y <= rect.bottom (); y += tilePixmap->height ())
+ {
+ for (int x = startx; x <= rect.right (); x += tilePixmap->width ())
+ {
+ painter->drawPixmap (x - rect.x (), y - rect.y (), *tilePixmap);
+ }
+ }
+
+#if DEBUG_KP_MAIN_WINDOW && 1 || 1
+{
+ const int totalTimerElapsed = totalTimer.elapsed ();
+ kDebug () << "\t\ttotal=" << totalTimerElapsed << endl;
+}
+#endif
+}
+
+
+#else
+
// public
void kpMainWindow::drawTransparentBackground (QPainter *painter,
int /*viewWidth*/, int /*viewHeight*/,
const QRect &rect,
bool isPreview)
{
+#if DEBUG_KP_MAIN_WINDOW && 1
+ kDebug () << "\tkpMainWindow::drawTransparentBackground(rect="
+ << rect << ")" << endl;
+ QTime totalTimer; totalTimer.start ();
+#endif
+
+
const int cellSize = !isPreview ? 16 : 10;
int starty = rect.y ();
@@ -877,8 +982,15 @@
}
}
painter->restore ();
-}
+#if DEBUG_KP_MAIN_WINDOW && 1 || 1
+{
+ const int totalTimerElapsed = totalTimer.elapsed ();
+ kDebug () << "\t\ttotal=" << totalTimerElapsed << endl;
+}
+#endif
+}
+#endif
// private slot
void kpMainWindow::slotUpdateCaption ()
|