QImage support for RGB30 formats

Adds basic support for 10-bit per color channel formats to QImage
and the XCB plugin. This will make it possible to paint to and from
these formats, but only at 8-bit per color channel accuracy.

This also fixes Qt5 applications on X11 with native 30bit depth.

[ChangeLog][QtGui][QImage] Added support for 10-bit per color channel image formats.

Task-number: QTBUG-25998
Change-Id: I93ccd3c74bfbb0bd94b352476e5fe58a94119e1f
Reviewed-by: Gunnar Sletta <gunnar.sletta@jollamobile.com>

1 files changed, 108 insertions, 9 deletions

diff --git a/src/gui/painting/qdrawhelper_p.h b/src/gui/painting/qdrawhelper_p.h
index 1c05fc305a..d6b557af01 100644
--- a/src/gui/painting/qdrawhelper_p.h
+++ b/src/gui/painting/qdrawhelper_p.h
@@ -672,6 +672,36 @@ static Q_ALWAYS_INLINE uint BYTE_MUL_RGB16_32(uint x, uint a) {
     return t;
 }
 
+#if defined(Q_CC_RVCT)
+#  pragma push
+#  pragma arm
+#endif
+static Q_ALWAYS_INLINE int qt_div_255(int x) { return (x + (x>>8) + 0x80) >> 8; }
+#if defined(Q_CC_RVCT)
+#  pragma pop
+#endif
+
+static Q_ALWAYS_INLINE uint BYTE_MUL_RGB30(uint x, uint a) {
+    uint xa = x >> 30;
+    uint xr = (x >> 20) & 0x3ff;
+    uint xg = (x >> 10) & 0x3ff;
+    uint xb = x & 0x3ff;
+    xa = qt_div_255(xa * a);
+    xr = qt_div_255(xr * a);
+    xg = qt_div_255(xg * a);
+    xb = qt_div_255(xb * a);
+    return (xa << 30) | (xr << 20) | (xg << 10) | xb;
+}
+
+static Q_ALWAYS_INLINE uint qAlphaRgb30(uint c)
+{
+    uint a = c >> 30;
+    a |= a << 2;
+    a |= a << 4;
+    return a;
+}
+
+
 // FIXME: Remove when all Qt modules have stopped using PREMUL and INV_PREMUL
 #define PREMUL(x) qPremultiply(x)
 #define INV_PREMUL(p) qUnpremultiply(p)
@@ -795,15 +825,6 @@ do {                                          \
     }                                         \
 } while (0)
 
-#if defined(Q_CC_RVCT)
-#  pragma push
-#  pragma arm
-#endif
-static Q_ALWAYS_INLINE int qt_div_255(int x) { return (x + (x>>8) + 0x80) >> 8; }
-#if defined(Q_CC_RVCT)
-#  pragma pop
-#endif
-
 inline ushort qConvertRgb32To16(uint c)
 {
    return (((c) >> 3) & 0x001f)
@@ -819,6 +840,84 @@ inline QRgb qConvertRgb16To32(uint c)
         | ((((c) << 8) & 0xf80000) | (((c) << 3) & 0x70000));
 }
 
+enum QtPixelOrder {
+    PixelOrderRGB,
+    PixelOrderBGR
+};
+
+template<enum QtPixelOrder> inline uint qConvertArgb32ToA2rgb30(QRgb);
+
+template<enum QtPixelOrder> inline uint qConvertRgb32ToRgb30(QRgb);
+
+template<enum QtPixelOrder> inline QRgb qConvertA2rgb30ToArgb32(uint c);
+
+template<>
+inline uint qConvertArgb32ToA2rgb30<PixelOrderBGR>(QRgb c)
+{
+    return (c & 0xc0000000)
+        | (((c << 22) & 0x3fc00000) | ((c << 14) & 0x00300000))
+        | (((c << 4) & 0x000ff000) | ((c >> 4) & 0x00000c00))
+        | (((c >> 14) & 0x000003fc) | ((c >> 22) & 0x00000003));
+}
+
+template<>
+inline uint qConvertArgb32ToA2rgb30<PixelOrderRGB>(QRgb c)
+{
+    return (c & 0xc0000000)
+        | (((c << 6) & 0x3fc00000) | ((c >> 2) & 0x00300000))
+        | (((c << 4) & 0x000ff000) | ((c >> 4) & 0x00000c00))
+        | (((c << 2) & 0x000003fc) | ((c >> 6) & 0x00000003));
+}
+
+template<>
+inline uint qConvertRgb32ToRgb30<PixelOrderBGR>(QRgb c)
+{
+    return 0xc0000000
+        | (((c << 22) & 0x3fc00000) | ((c << 14) & 0x00300000))
+        | (((c << 4) & 0x000ff000) | ((c >> 4) & 0x00000c00))
+        | (((c >> 14) & 0x000003fc) | ((c >> 22) & 0x00000003));
+}
+
+template<>
+inline uint qConvertRgb32ToRgb30<PixelOrderRGB>(QRgb c)
+{
+    return 0xc0000000
+        | (((c << 6) & 0x3fc00000) | ((c >> 2) & 0x00300000))
+        | (((c << 4) & 0x000ff000) | ((c >> 4) & 0x00000c00))
+        | (((c << 2) & 0x000003fc) | ((c >> 6) & 0x00000003));
+}
+
+template<>
+inline QRgb qConvertA2rgb30ToArgb32<PixelOrderBGR>(uint c)
+{
+    uint a = c >> 30;
+    a |= a << 2;
+    a |= a << 4;
+    return (a << 24)
+        | ((c << 14) & 0x00ff0000)
+        | ((c >> 4) & 0x0000ff00)
+        | ((c >> 22) & 0x000000ff);
+}
+
+template<>
+inline QRgb qConvertA2rgb30ToArgb32<PixelOrderRGB>(uint c)
+{
+    uint a = c >> 30;
+    a |= a << 2;
+    a |= a << 4;
+    return (a << 24)
+        | ((c >> 6) & 0x00ff0000)
+        | ((c >> 4) & 0x0000ff00)
+        | ((c >> 2) & 0x000000ff);
+}
+
+inline uint qRgbSwapRgb30(uint c)
+{
+    const uint ag = c & 0xc00ffc00;
+    const uint rb = c & 0x3ff003ff;
+    return ag | (rb << 20) | (rb >> 20);
+}
+
 inline int qRed565(quint16 rgb) {
     const int r = (rgb & 0xf800);
     return (r >> 8) | (r >> 13);