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authorRhys Weatherley <rhys.weatherley@nokia.com>2010-01-06 22:57:54 (GMT)
committerRhys Weatherley <rhys.weatherley@nokia.com>2010-01-06 22:57:54 (GMT)
commit58112b1e251c03b0a72511508712f9a67ce84d25 (patch)
tree510325d673e65ee5a1e34065f059e0491fb2534d /src/gui/image/qimage.cpp
parent0647ea310c3880a0b1457f750dd6d092666c14de (diff)
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Add QImage::constBits() and QImage::constScanLine()
QImage::bits() and QImage::scanLine() can create deep copies if the QImage is not const. The constBits() and constScanLine() functions make things more explicit and less error-prone. Reviewed-by: Daniel Pope
Diffstat (limited to 'src/gui/image/qimage.cpp')
-rw-r--r--src/gui/image/qimage.cpp40
1 files changed, 38 insertions, 2 deletions
diff --git a/src/gui/image/qimage.cpp b/src/gui/image/qimage.cpp
index ec8dd88..fc1107d 100644
--- a/src/gui/image/qimage.cpp
+++ b/src/gui/image/qimage.cpp
@@ -1832,7 +1832,7 @@ void QImage::setColor(int i, QRgb c)
qAlpha() to access the pixels.
\sa bytesPerLine(), bits(), {QImage#Pixel Manipulation}{Pixel
- Manipulation}
+ Manipulation}, constScanLine()
*/
uchar *QImage::scanLine(int i)
{
@@ -1862,6 +1862,28 @@ const uchar *QImage::scanLine(int i) const
/*!
+ Returns a pointer to the pixel data at the scanline with index \a
+ i. The first scanline is at index 0.
+
+ The scanline data is aligned on a 32-bit boundary.
+
+ Note that QImage uses \l{Implicit Data Sharing} {implicit data
+ sharing}, but this function does \e not perform a deep copy of the
+ shared pixel data, because the returned data is const.
+
+ \sa scanLine(), constBits()
+ \since 4.7
+*/
+const uchar *QImage::constScanLine(int i) const
+{
+ if (!d)
+ return 0;
+
+ Q_ASSERT(i >= 0 && i < height());
+ return d->data + i * d->bytes_per_line;
+}
+
+/*!
Returns a pointer to the first pixel data. This is equivalent to
scanLine(0).
@@ -1870,7 +1892,7 @@ const uchar *QImage::scanLine(int i) const
data, thus ensuring that this QImage is the only one using the
current return value.
- \sa scanLine(), byteCount()
+ \sa scanLine(), byteCount(), constBits()
*/
uchar *QImage::bits()
{
@@ -1898,6 +1920,20 @@ const uchar *QImage::bits() const
}
+/*!
+ Returns a pointer to the first pixel data.
+
+ Note that QImage uses \l{Implicit Data Sharing} {implicit data
+ sharing}, but this function does \e not perform a deep copy of the
+ shared pixel data, because the returned data is const.
+
+ \sa bits(), constScanLine()
+ \since 4.7
+*/
+const uchar *QImage::constBits() const
+{
+ return d ? d->data : 0;
+}
/*!
\fn void QImage::reset()