Cocoa: Export QImage <-> CGImage conversion funcs.

For implementing to/fromMacCGImageRef in QtMacExtras.

These do not depend on internal Qt state. The main
reason for exporting them is to keep the implementation
in one place to ease maintenance.

Refactor qt_mac_cg_context to support QImage.
Add qt_mac_toQImage.

Change-Id: Ia9c226ed52d087b2c6b47aa8210ed8f2645b9cf2
Reviewed-by: Gabriel de Dietrich <gabriel.dedietrich@digia.com>

src/plugins/platforms/cocoa/qcocoahelpers.h

@@ -158,8 +158,9 @@ public:
     }
 };
 
-CGContextRef qt_mac_cg_context(const QPaintDevice *pdev);
+CGContextRef qt_mac_cg_context(QPaintDevice *pdev);
 CGImageRef qt_mac_toCGImage(const QImage &qImage, bool isMask, uchar **dataCopy);
+QImage qt_mac_toQImage(CGImageRef image);
 
 QT_END_NAMESPACE
 

src/plugins/platforms/cocoa/qcocoahelpers.mm

@@ -719,35 +719,38 @@ QString qt_mac_removeAmpersandEscapes(QString s)
  \warning This function is only available on Mac OS X.
  \warning This function is duplicated in qmacstyle_mac.mm
  */
-CGContextRef qt_mac_cg_context(const QPaintDevice *pdev)
+CGContextRef qt_mac_cg_context(QPaintDevice *pdev)
 {
-    if (pdev->devType() == QInternal::Pixmap) {
+    // In Qt 5, QWidget and QPixmap (and QImage) paint devices are all QImages under the hood.
+    QImage *image = 0;
+    if (pdev->devType() == QInternal::Image) {
+        image = static_cast<QImage *>(pdev);
+    } else if (pdev->devType() == QInternal::Pixmap) {
+
         const QPixmap *pm = static_cast<const QPixmap*>(pdev);
+        QPlatformPixmap *data = const_cast<QPixmap *>(pm)->data_ptr().data();
+        if (data && data->classId() == QPlatformPixmap::RasterClass) {
+            image = data->buffer();
+        } else {
+            qDebug() << "qt_mac_cg_context: Unsupported pixmap class";
+        }
+    } else if (pdev->devType() == QInternal::Widget) {
+        // TODO test: image = static_cast<QImage *>(static_cast<const QWidget *>(pdev)->backingStore()->paintDevice());
+        qDebug() << "qt_mac_cg_context: not implemented: Widget class";
+    }
+
+    if (!image)
+        return 0; // Context type not supported.
+
     CGColorSpaceRef colorspace = qt_mac_colorSpaceForDeviceType(pdev);
     uint flags = kCGImageAlphaPremultipliedFirst;
     flags |= kCGBitmapByteOrder32Host;
     CGContextRef ret = 0;
-
-        QPlatformPixmap *data = const_cast<QPixmap *>(pm)->data_ptr().data();
-        if (data && data->classId() == QPlatformPixmap::RasterClass) {
-            QImage *image = data->buffer();
     ret = CGBitmapContextCreate(image->bits(), image->width(), image->height(),
                                 8, image->bytesPerLine(), colorspace, flags);
-        } else {
-            qDebug() << "qt_mac_cg_context: Unsupported pixmap class";
-        }
-
-        CGContextTranslateCTM(ret, 0, pm->height());
+    CGContextTranslateCTM(ret, 0, image->height());
     CGContextScaleCTM(ret, 1, -1);
     return ret;
-    } else if (pdev->devType() == QInternal::Widget) {
-        //CGContextRef ret = static_cast<CGContextRef>(static_cast<const QWidget *>(pdev)->macCGHandle());
-        ///CGContextRetain(ret);
-        //return ret;
-        qDebug() << "qt_mac_cg_context: not implemented: Widget class";
-        return 0;
-    }
-    return 0;
 }
 
 CGImageRef qt_mac_toCGImage(const QImage &qImage, bool isMask, uchar **dataCopy)
@@ -841,4 +844,18 @@ CGImageRef qt_mac_toCGImage(const QImage &qImage, bool isMask, uchar **dataCopy)
     return cgImage;
 }
 
+QImage qt_mac_toQImage(CGImageRef image)
+{
+    const size_t w = CGImageGetWidth(image),
+                 h = CGImageGetHeight(image);
+    QImage ret(w, h, QImage::Format_ARGB32_Premultiplied);
+    ret.fill(Qt::transparent);
+    CGRect rect = CGRectMake(0, 0, w, h);
+    CGContextRef ctx = qt_mac_cg_context(&ret);
+    qt_mac_drawCGImage(ctx, &rect, image);
+    CGContextRelease(ctx);
+    return ret;
+}
+
+
 QT_END_NAMESPACE

src/plugins/platforms/cocoa/qcocoanativeinterface.h

@@ -42,6 +42,8 @@
 #ifndef QCOCOANATIVEINTERFACE_H
 #define QCOCOANATIVEINTERFACE_H
 
+#include <ApplicationServices/ApplicationServices.h>
+
 #include <qpa/qplatformnativeinterface.h>
 
 QT_BEGIN_NAMESPACE
@@ -96,6 +98,10 @@ private:
 
     // Dock menu support
     static void setDockMenu(QPlatformMenu *platformMenu);
+
+    // QImage <-> CGImage conversion functions
+    static CGImageRef qImageToCGImage(const QImage &image);
+    static QImage cgImageToQImage(CGImageRef image);
 };
 
 #endif // QCOCOANATIVEINTERFACE_H

src/plugins/platforms/cocoa/qcocoanativeinterface.mm

@@ -45,6 +45,7 @@
 #include "qcocoamenu.h"
 #include "qcocoamenubar.h"
 #include "qmacmime.h"
+#include "qcocoahelpers.h"
 
 #include <qbytearray.h>
 #include <qwindow.h>
@@ -108,6 +109,10 @@ QPlatformNativeInterface::NativeResourceForIntegrationFunction QCocoaNativeInter
         return NativeResourceForIntegrationFunction(QCocoaNativeInterface::registerDraggedTypes);
     if (resource.toLower() == "setdockmenu")
         return NativeResourceForIntegrationFunction(QCocoaNativeInterface::setDockMenu);
+    if (resource.toLower() == "qimagetocgimage")
+        return NativeResourceForIntegrationFunction(QCocoaNativeInterface::qImageToCGImage);
+    if (resource.toLower() == "cgimagetoqimage")
+        return NativeResourceForIntegrationFunction(QCocoaNativeInterface::cgImageToQImage);
 
     return 0;
 }
@@ -183,4 +188,15 @@ void QCocoaNativeInterface::setDockMenu(QPlatformMenu *platformMenu)
     [NSApp setDockMenu: menu];
 }
 
+CGImageRef QCocoaNativeInterface::qImageToCGImage(const QImage &image)
+{
+    return qt_mac_toCGImage(image, false, 0);
+}
+
+QImage QCocoaNativeInterface::cgImageToQImage(CGImageRef image)
+{
+    return qt_mac_toQImage(image);
+}
+
+
 QT_END_NAMESPACE

src/plugins/platforms/cocoa/qcocoatheme.mm

@@ -53,6 +53,7 @@
 #include "qcocoamenuitem.h"
 #include "qcocoamenu.h"
 #include "qcocoamenubar.h"
+#include "qcocoahelpers.h"
 
 #include <QtCore/qfileinfo.h>
 #include <QtGui/private/qguiapplication_p.h>
@@ -137,9 +138,6 @@ const QFont *QCocoaTheme::font(Font type) const
     return m_fonts.value(type, 0);
 }
 
-// Defined in qpaintengine_mac.mm
-extern CGContextRef qt_mac_cg_context(const QPaintDevice *pdev);
-
 //! \internal
 QPixmap qt_mac_convert_iconref(const IconRef icon, int width, int height)
 {