Speed up QPixmap::width(), height(), isNull() and depth().

This change moves the w, h, d variables to QPixmapData and introduces
is_null to keep track of nullness. This is possible only because
QPixmapData is internal API; otherwise we'd have to be smarter.

The optimization makes the QPixmap::width() function take 7 instructions,
down from 34 before. For the calculator demo in the declarative ui branch
this reduces a block of 750000 instructions (out of 30000000) to around
100000-150000 instructions.

Tested on Windows, Linux, Mac. Raster, X11 and OpenGL paint engines. Have
not tested the DirectFB engine.

Reviewed-by: Trond

9 files changed, 47 insertions, 18 deletions

diff --git a/src/gui/image/qpixmap.cpp b/src/gui/image/qpixmap.cpp
index 6da291c..56c3a29 100644
--- a/src/gui/image/qpixmap.cpp
+++ b/src/gui/image/qpixmap.cpp
@@ -552,7 +552,7 @@ bool QPixmap::isQBitmap() const
 */
 bool QPixmap::isNull() const
 {
-    return data->width() == 0;
+    return data->isNull();
 }
 
 /*!
diff --git a/src/gui/image/qpixmap.h b/src/gui/image/qpixmap.h
index e4faebd..d1e2ecb 100644
--- a/src/gui/image/qpixmap.h
+++ b/src/gui/image/qpixmap.h
@@ -79,11 +79,11 @@ public:
     QPixmap &operator=(const QPixmap &);
     operator QVariant() const;
 
-    bool isNull() const;
+    bool isNull() const; // ### Qt 5: make inline
     int devType() const;
 
-    int width() const;
-    int height() const;
+    int width() const; // ### Qt 5: make inline
+    int height() const; // ### Qt 5: make inline
     QSize size() const;
     QRect rect() const;
     int depth() const;
diff --git a/src/gui/image/qpixmap_mac.cpp b/src/gui/image/qpixmap_mac.cpp
index ca9d497..b40694a 100644
--- a/src/gui/image/qpixmap_mac.cpp
+++ b/src/gui/image/qpixmap_mac.cpp
@@ -168,7 +168,7 @@ static inline QRgb qt_conv16ToRgb(ushort c) {
 QSet<QMacPixmapData*> QMacPixmapData::validDataPointers;
 
 QMacPixmapData::QMacPixmapData(PixelType type)
-    : QPixmapData(type, MacClass), w(0), h(0), d(0), has_alpha(0), has_mask(0),
+    : QPixmapData(type, MacClass), has_alpha(0), has_mask(0),
       uninit(true), pixels(0), pixelsToFree(0), bytesPerRow(0),
       cg_data(0), cg_dataBeingReleased(0), cg_mask(0),
 #ifndef QT_MAC_NO_QUICKDRAW
@@ -188,11 +188,13 @@ void QMacPixmapData::resize(int width, int height)
 
     w = width;
     h = height;
+    is_null = (w <= 0 || h <= 0);
     d = (pixelType() == BitmapType ? 1 : 32);
     bool make_null = w <= 0 || h <= 0;                // create null pixmap
     if (make_null || d == 0) {
         w = 0;
         h = 0;
+        is_null = true;
         d = 0;
         if (!make_null)
             qWarning("Qt: QPixmap: Invalid pixmap parameters");
@@ -231,6 +233,7 @@ void QMacPixmapData::fromImage(const QImage &img,
 
     w = img.width();
     h = img.height();
+    is_null = (w <= 0 || h <= 0);
     d = (pixelType() == BitmapType ? 1 : img.depth());
 
     QImage image = img;
diff --git a/src/gui/image/qpixmap_mac_p.h b/src/gui/image/qpixmap_mac_p.h
index 66797ed..a3ff0d3 100644
--- a/src/gui/image/qpixmap_mac_p.h
+++ b/src/gui/image/qpixmap_mac_p.h
@@ -83,7 +83,6 @@ public:
     QPaintEngine* paintEngine() const;
 
 private:
-    int w, h, d;
 
     uint has_alpha : 1, has_mask : 1, uninit : 1;
 
diff --git a/src/gui/image/qpixmap_raster.cpp b/src/gui/image/qpixmap_raster.cpp
index 2c57ede..9cc896b 100644
--- a/src/gui/image/qpixmap_raster.cpp
+++ b/src/gui/image/qpixmap_raster.cpp
@@ -85,6 +85,10 @@ void QRasterPixmapData::resize(int width, int height)
 #endif
 
     image = QImage(width, height, format);
+    w = width;
+    h = height;
+    d = image.depth();
+    is_null = (w <= 0 || h <= 0);
 
     if (pixelType() == BitmapType && !image.isNull()) {
         image.setNumColors(2);
@@ -168,6 +172,10 @@ void QRasterPixmapData::fromImage(const QImage &sourceImage,
         }
     }
 #endif
+    w = image.d->width;
+    h = image.d->height;
+    d = image.d->depth;
+    is_null = (w <= 0 || h <= 0);
 
     setSerialNumber(image.serialNumber());
 }
@@ -329,9 +337,9 @@ int QRasterPixmapData::metric(QPaintDevice::PaintDeviceMetric metric) const
     // override the image dpi with the screen dpi when rendering to a pixmap
     switch (metric) {
     case QPaintDevice::PdmWidth:
-        return d->width;
+        return w;
     case QPaintDevice::PdmHeight:
-        return d->height;
+        return h;
     case QPaintDevice::PdmWidthMM:
         return qRound(d->width * 25.4 / qt_defaultDpiX());
     case QPaintDevice::PdmHeightMM:
@@ -339,7 +347,7 @@ int QRasterPixmapData::metric(QPaintDevice::PaintDeviceMetric metric) const
     case QPaintDevice::PdmNumColors:
         return d->colortable.size();
     case QPaintDevice::PdmDepth:
-        return d->depth;
+        return this->d;
     case QPaintDevice::PdmDpiX: // fall-through
     case QPaintDevice::PdmPhysicalDpiX:
         return qt_defaultDpiX();
diff --git a/src/gui/image/qpixmap_x11.cpp b/src/gui/image/qpixmap_x11.cpp
index b7fe92a..86cf515 100644
--- a/src/gui/image/qpixmap_x11.cpp
+++ b/src/gui/image/qpixmap_x11.cpp
@@ -312,7 +312,7 @@ static int qt_pixmap_serial = 0;
 int Q_GUI_EXPORT qt_x11_preferred_pixmap_depth = 0;
 
 QX11PixmapData::QX11PixmapData(PixelType type)
-    : QPixmapData(type, X11Class), hd(0), w(0), h(0), d(0),
+    : QPixmapData(type, X11Class), hd(0),
       uninit(true), read_only(false), x11_mask(0), picture(0), mask_picture(0), hd2(0),
       share_mode(QPixmap::ImplicitlyShared), pengine(0)
 {
@@ -324,6 +324,7 @@ void QX11PixmapData::resize(int width, int height)
 
     w = width;
     h = height;
+    is_null = (w <= 0 || h <= 0);
 
     if (defaultScreen >= 0 && defaultScreen != xinfo.screen()) {
         QX11InfoData* xd = xinfo.getX11Data(true);
@@ -347,6 +348,7 @@ void QX11PixmapData::resize(int width, int height)
     if (make_null || d == 0) {
         w = 0;
         h = 0;
+        is_null = true;
         hd = 0;
         picture = 0;
         d = 0;
@@ -375,6 +377,7 @@ void QX11PixmapData::fromImage(const QImage &img,
     w = img.width();
     h = img.height();
     d = img.depth();
+    is_null = (w <= 0 || h <= 0);
 
     if (defaultScreen >= 0 && defaultScreen != xinfo.screen()) {
         QX11InfoData* xd = xinfo.getX11Data(true);
@@ -395,6 +398,7 @@ void QX11PixmapData::fromImage(const QImage &img,
 
     if (uint(w) >= 32768 || uint(h) >= 32768) {
         w = h = 0;
+        is_null = true;
         return;
     }
 
@@ -1109,6 +1113,7 @@ void QX11PixmapData::bitmapFromImage(const QImage &image)
     w = img.width();
     h = img.height();
     d = 1;
+    is_null = (w <= 0 || h <= 0);
     int bpl = (w + 7) / 8;
     int ibpl = img.bytesPerLine();
     if (bpl != ibpl) {
@@ -1876,6 +1881,7 @@ QPixmap QX11PixmapData::transformed(const QTransform &transform,
         x11Data->d = d;
         x11Data->w = w;
         x11Data->h = h;
+        x11Data->is_null = (w <= 0 || h <= 0);
         x11Data->hd = (Qt::HANDLE)XCreatePixmap(X11->display,
                                                 RootWindow(X11->display, xinfo.screen()),
                                                 w, h, d);
@@ -2132,6 +2138,7 @@ void QX11PixmapData::copy(const QPixmapData *data, const QRect &rect)
     d = x11Data->d;
     w = rect.width();
     h = rect.height();
+    is_null = (w <= 0 || h <= 0);
     hd = (Qt::HANDLE)XCreatePixmap(X11->display,
                                    RootWindow(X11->display, x11Data->xinfo.screen()),
                                    w, h, d);
@@ -2250,6 +2257,7 @@ QPixmap QPixmap::fromX11Pixmap(Qt::HANDLE pixmap, QPixmap::ShareMode mode)
     data->uninit = false;
     data->w = width;
     data->h = height;
+    data->is_null = (width <= 0 || height <= 0);
     data->d = depth;
     data->hd = pixmap;
 
diff --git a/src/gui/image/qpixmap_x11_p.h b/src/gui/image/qpixmap_x11_p.h
index addcc7c..3de9a0f 100644
--- a/src/gui/image/qpixmap_x11_p.h
+++ b/src/gui/image/qpixmap_x11_p.h
@@ -108,8 +108,6 @@ private:
 
     Qt::HANDLE hd;
 
-    int w, h;
-    short d;
     uint uninit : 1;
     uint read_only : 1;
 
diff --git a/src/gui/image/qpixmapdata.cpp b/src/gui/image/qpixmapdata.cpp
index 094d7e4..b50d664 100644
--- a/src/gui/image/qpixmapdata.cpp
+++ b/src/gui/image/qpixmapdata.cpp
@@ -49,9 +49,17 @@ const uchar qt_pixmap_bit_mask[] = { 0x01, 0x02, 0x04, 0x08,
                                      0x10, 0x20, 0x40, 0x80 };
 
 QPixmapData::QPixmapData(PixelType pixelType, int objectId)
-    : ref(0), detach_no(0), type(pixelType), id(objectId), ser_no(0), is_cached(false)
+    : w(0),
+      h(0),
+      d(0),
+      is_null(true),
+      ref(0),
+      detach_no(0),
+      type(pixelType),
+      id(objectId),
+      ser_no(0),
+      is_cached(false)
 {
-
 }
 
 QPixmapData::~QPixmapData()
diff --git a/src/gui/image/qpixmapdata_p.h b/src/gui/image/qpixmapdata_p.h
index 4c49dd2..29dafaf 100644
--- a/src/gui/image/qpixmapdata_p.h
+++ b/src/gui/image/qpixmapdata_p.h
@@ -99,13 +99,18 @@ public:
 
     virtual QImage* buffer();
 
-    int width() const { return metric(QPaintDevice::PdmWidth); }
-    int height() const { return metric(QPaintDevice::PdmHeight); }
-    int numColors() const { return metric(QPaintDevice::PdmNumColors); }
-    int depth() const { return metric(QPaintDevice::PdmDepth); }
+    inline int width() const { return w; }
+    inline int height() const { return h; }
+    inline int numColors() const { return metric(QPaintDevice::PdmNumColors); }
+    inline int depth() const { return d; }
+    inline bool isNull() const { return is_null; }
 
 protected:
     void setSerialNumber(int serNo);
+    int w;
+    int h;
+    int d;
+    bool is_null;
 
 private:
     friend class QPixmap;