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我在這裏完全喪失...的QPixmap fromImage導致分段故障
我想一個QImage的轉換爲QPixmap的，但我的程序保持與以下堆棧跟蹤崩潰。奇怪的是，如果我指定的QRectF沒有左上角的點（0,0），它會正常工作。我知道QImage也有一個複製方法，但那也是失敗的（沒有有用的堆棧跟蹤），所以我想我會嘗試使用Pixmaps來代替...... Line的4/5的堆棧跟蹤是我的，但我'米基本上是做以下
QImage _drawing = QImage(1024, 1024);
// fill _drawing with some data
QRect i_work = QRect(1, 1, 10, 10);
QRect i_break = QRect(0, 0, 10, 10);
QPixmap foo = QPixmap::fromImage(_drawing);
// QPixmap good = foo.copy(i_work); // I work
QPixmap broken = foo.copy(i_break); // Segmentation fault...
堆棧跟蹤：
Program received signal SIGSEGV, Segmentation fault.
0x01f44024 in QBasicAtomicInt::ref (this=0xabababab)
at ../../include/QtCore/../../src/corelib/arch/qatomic_i386.h:120
120 ../../include/QtCore/../../src/corelib/arch/qatomic_i386.h: No such file
or directory.
in ../../include/QtCore/../../src/corelib/arch/qatomic_i386.h
(gdb) bt
#0 0x01f44024 in QBasicAtomicInt::ref (this=0xabababab)
at ../../include/QtCore/../../src/corelib/arch/qatomic_i386.h:120
#1 0x01964d3e in QImage::QImage (this=0x28cc70, image=...)
at image\qimage.cpp:1125
#2 0x01990682 in QRasterPixmapData::fromImage (this=0xc391a00,
sourceImage=..., flags=...) at image\qpixmap_raster.cpp:151
#3 0x019862ab in QPixmap::fromImage (image=..., flags=...)
at image\qpixmap.cpp:2031
#4 0x00423fdc in TxImage::getSelection (this=0xc3b6cb0, selection_area=...)
at TxImage.cpp:207
#5 0x004421e2 in RomView::mouseReleaseEvent (this=0xc397978, event=0x28d5fc)
at RomView.cpp:261
#6 0x019241a0 in QWidget::event (this=0xc397978, event=0x28d5fc)
at kernel\qwidget.cpp:8187
#7 0x01c9e6bc in QFrame::event (this=0xc397978, e=0x28d5fc)
at widgets\qframe.cpp:557
#8 0x01d2bf0f in QAbstractScrollArea::viewportEvent (this=0xc397978,
e=0x28d5fc) at widgets\qabstractscrollarea.cpp:1043
#9 0x01e9aae6 in QGraphicsView::viewportEvent (this=0xc397978,
event=0x28d5fc) at graphicsview\qgraphicsview.cpp:2862
#10 0x01f86a13 in QAbstractScrollAreaPrivate::viewportEvent (this=0xc3969f8,
event=0x28d5fc) at widgets//qabstractscrollarea_p.h:100
#11 0x01f8506c in QAbstractScrollAreaFilter::eventFilter (this=0xbfa7388, o=
0xbf43978, e=0x28d5fc) at widgets//qabstractscrollarea_p.h:116
#12 0x6a1ffc73 in QCoreApplicationPrivate::sendThroughObjectEventFilters (
this=0xa7a46d8, receiver=0xbf43978, event=0x28d5fc)
at kernel\qcoreapplication.cpp:847
#13 0x018d96e5 in QApplicationPrivate::notify_helper (this=0xa7a46d8,
receiver=0xbf43978, e=0x28d5fc) at kernel\qapplication.cpp:4392
#14 0x018d7909 in QApplication::notify (this=0x28fe34, receiver=0xbf43978,
e=0x28d5fc) at kernel\qapplication.cpp:3959
#15 0x6a1ff9dc in QCoreApplication::notifyInternal (this=0x28fe34,
receiver=0xbf43978, event=0x28d5fc) at kernel\qcoreapplication.cpp:732
#16 0x01f4d53e in QCoreApplication::sendSpontaneousEvent (receiver=0xbf43978,
event=0x28d5fc)
at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:218
#17 0x018d6118 in QApplicationPrivate::sendMouseEvent (receiver=0xbf43978,
event=0x28d5fc, alienWidget=0xc3adb70, nativeWidget=0x28fd60,
buttonDown=0x237941c, lastMouseReceiver=..., spontaneous=true)
at kernel\qapplication.cpp:3056
#18 0x0193fc63 in QETWidget::translateMouseEvent (this=0x28fd60, msg=...)
at kernel\qapplication_win.cpp:3317
#19 0x0193aaa6 in QtWndProc (hwnd=0x130fb8, message=514, wParam=0,
lParam=5373956) at kernel\qapplication_win.cpp:1657
#20 0x762c62fa in USER32!OffsetRect() from C:\Windows\syswow64\user32.dll
#21 0x900010c2 in ??()
#22 0x90909090 in ??()
#23 0x00df7d80 in operator+()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb)
我向你保證，qatomic_i386.h存在，並且在看線120 ...
112: inline bool QBasicAtomicInt::ref()
113: {
114: unsigned char ret;
115: asm volatile("lock\n"
116: "incl %0\n"
117: "setne %1"
118: : "=m" (_q_value), "=qm" (ret)
119: : "m" (_q_value)
120: : "memory");
121: return ret != 0;
122: }
QBasicAtomicInt無關緊要，因爲傳遞給它的值已經無效。這表明QImage中的QImageData，d未被初始化。我查看了QImage的所有構造函數，並且它們都初始化了d，所以它很奇怪。 – sep 2011-05-30 09:19:23