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authorHolger Hans Peter Freyther <zecke@selfish.org>2009-10-13 00:59:32 (GMT)
committerAndreas Aardal Hanssen <andreas.aardal.hanssen@nokia.com>2009-12-23 12:27:46 (GMT)
commit3de151493f75dc52e693f84ef66ff1a86c79d8e3 (patch)
treea90a556ca46a0d2e3d49d18966c39c02177774b6 /src/plugins
parent5c0a117f62607ed439cdfa3d94aaef627c47ce8a (diff)
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gif: 10% speedup on microbenchmark on QImageReader
On the microbenchmark of what is executed during pure pageloading in regarding to QImageReader this is an improvement. Do not use the non const QImage::scanLine as this will go through the QImage::detach all the time making QImage::scanLine show up in the profile. Introduce a FAST_SCAN_LINE that is doing the scanLine calculation on local variables. Reviewed-by: Andreas
Diffstat (limited to 'src/plugins')
-rw-r--r--src/plugins/imageformats/gif/qgifhandler.cpp40
1 files changed, 26 insertions, 14 deletions
diff --git a/src/plugins/imageformats/gif/qgifhandler.cpp b/src/plugins/imageformats/gif/qgifhandler.cpp
index c95b63c..dee0e52 100644
--- a/src/plugins/imageformats/gif/qgifhandler.cpp
+++ b/src/plugins/imageformats/gif/qgifhandler.cpp
@@ -54,6 +54,10 @@ QT_BEGIN_NAMESPACE
#define Q_TRANSPARENT 0x00ffffff
+// avoid going through QImage::scanLine() which calls detach
+#define FAST_SCAN_LINE(bits, bpl, y) (bits + (y) * bpl)
+
+
/*
Incremental image decoder for GIF image format.
@@ -135,7 +139,7 @@ private:
int frame;
bool out_of_bounds;
bool digress;
- void nextY(QImage *image);
+ void nextY(unsigned char *bits, int bpl);
void disposePrevious(QImage *image);
};
@@ -232,6 +236,10 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
// CompuServe Incorporated. GIF(sm) is a Service Mark property of
// CompuServe Incorporated."
+ image->detach();
+ int bpl = image->bytesPerLine();
+ unsigned char *bits = image->bits();
+
#define LM(l, m) (((m)<<8)|l)
digress = false;
const int initial = length;
@@ -335,7 +343,9 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
QImage::Format format = trans_index >= 0 ? QImage::Format_ARGB32 : QImage::Format_RGB32;
if (image->isNull()) {
(*image) = QImage(swidth, sheight, format);
- memset(image->bits(), 0, image->byteCount());
+ bpl = image->bytesPerLine();
+ bits = image->bits();
+ memset(bits, 0, image->byteCount());
// ### size of the upcoming frame, should rather
// be known before decoding it.
@@ -393,11 +403,13 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
backingstore = QImage(qMax(backingstore.width(), w),
qMax(backingstore.height(), h),
QImage::Format_RGB32);
- memset(image->bits(), 0, image->byteCount());
+ memset(bits, 0, image->byteCount());
}
+ const int dest_bpl = backingstore.bytesPerLine();
+ unsigned char *dest_data = backingstore.bits();
for (int ln=0; ln<h; ln++) {
- memcpy(backingstore.scanLine(ln),
- image->scanLine(t+ln)+l, w*sizeof(QRgb));
+ memcpy(FAST_SCAN_LINE(dest_data, dest_bpl, ln),
+ FAST_SCAN_LINE(bits, bpl, t+ln) + l, w*sizeof(QRgb));
}
}
@@ -470,14 +482,14 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
if (needfirst) {
firstcode=oldcode=code;
if (!out_of_bounds && image->height() > y && firstcode!=trans_index)
- ((QRgb*)image->scanLine(y))[x] = color(firstcode);
+ ((QRgb*)FAST_SCAN_LINE(bits, bpl, y))[x] = color(firstcode);
x++;
if (x>=swidth) out_of_bounds = true;
needfirst=false;
if (x>=left+width) {
x=left;
out_of_bounds = left>=swidth || y>=sheight;
- nextY(image);
+ nextY(bits, bpl);
}
} else {
incode=code;
@@ -515,7 +527,7 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
const QRgb *map = lcmap ? localcmap : globalcmap;
QRgb *line = 0;
if (!out_of_bounds && h > y)
- line = (QRgb*)image->scanLine(y);
+ line = (QRgb*)FAST_SCAN_LINE(bits, bpl, y);
while (sp>stack) {
const uchar index = *(--sp);
if (!out_of_bounds && h > y && index!=trans_index) {
@@ -529,9 +541,9 @@ int QGIFFormat::decode(QImage *image, const uchar *buffer, int length,
if (x>=left+width) {
x=left;
out_of_bounds = left>=swidth || y>=sheight;
- nextY(image);
+ nextY(bits, bpl);
if (!out_of_bounds && h > y)
- line = (QRgb*)image->scanLine(y);
+ line = (QRgb*)FAST_SCAN_LINE(bits, bpl, y);
}
}
}
@@ -644,7 +656,7 @@ void QGIFFormat::fillRect(QImage *image, int col, int row, int w, int h, QRgb co
}
}
-void QGIFFormat::nextY(QImage *image)
+void QGIFFormat::nextY(unsigned char *bits, int bpl)
{
int my;
switch (interlace) {
@@ -660,7 +672,7 @@ void QGIFFormat::nextY(QImage *image)
// Don't dup with transparency
if (trans_index < 0) {
for (i=1; i<=my; i++) {
- memcpy(image->scanLine(y+i)+left*sizeof(QRgb), image->scanLine(y)+left*sizeof(QRgb),
+ memcpy(FAST_SCAN_LINE(bits, bpl, y+i)+left*sizeof(QRgb), FAST_SCAN_LINE(bits, bpl, y)+left*sizeof(QRgb),
(right-left+1)*sizeof(QRgb));
}
}
@@ -689,7 +701,7 @@ void QGIFFormat::nextY(QImage *image)
// Don't dup with transparency
if (trans_index < 0) {
for (i=1; i<=my; i++) {
- memcpy(image->scanLine(y+i)+left*sizeof(QRgb), image->scanLine(y)+left*sizeof(QRgb),
+ memcpy(FAST_SCAN_LINE(bits, bpl, y+i)+left*sizeof(QRgb), FAST_SCAN_LINE(bits, bpl, y)+left*sizeof(QRgb),
(right-left+1)*sizeof(QRgb));
}
}
@@ -713,7 +725,7 @@ void QGIFFormat::nextY(QImage *image)
// Don't dup with transparency
if (trans_index < 0) {
for (i=1; i<=my; i++) {
- memcpy(image->scanLine(y+i)+left*sizeof(QRgb), image->scanLine(y)+left*sizeof(QRgb),
+ memcpy(FAST_SCAN_LINE(bits, bpl, y+i)+left*sizeof(QRgb), FAST_SCAN_LINE(bits, bpl, y)+left*sizeof(QRgb),
(right-left+1)*sizeof(QRgb));
}
}