libgui: Added de::Image, a wrapper that extends QImage

The pixel formats supported by QImage are only partially compatible
with OpenGL (ES). de::Image defines a full set of GLES friendly
formats that can be used to pass raw pixel data (or QImages) to
GLTexture.

doomsday/libgui/include/de/Image

@@ -0,0 +1 @@
+#include "gui/image.h"

doomsday/libgui/include/de/gui/image.h

@@ -0,0 +1,146 @@
+/** @file image.h  Wrapper over QImage.
+ *
+ * @authors Copyright (c) 2013 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small> 
+ */
+
+#ifndef LIBGUI_IMAGE_H
+#define LIBGUI_IMAGE_H
+
+#include <utility>
+#include <QImage>
+#include <de/Vector>
+#include <de/ByteRefArray>
+
+#include "libgui.h"
+
+namespace de {
+
+/**
+ * Thin wrapper over QImage allowing use of some custom/raw image formats.
+ *
+ * Some image formats do not allow drawing. As a rule, all QImage-based formats
+ * support drawing (via QPainter).
+ *
+ * @todo Merge image_s and the related Image_* routines into here.
+ */
+class LIBGUI_PUBLIC Image
+{
+public:
+    /**
+     * Supported GL-friendly formats. Note that all QImage formats cannot be
+     * uploaded to OpenGL.
+     */
+    enum Format
+    {
+        UseQImageFormat,    ///< May not be GL friendly.
+
+        Luminance_8,
+        LuminanceAlpha_88,
+        Alpha_8,
+        RGB_555,
+        RGB_565,
+        RGB_444,
+        RGB_888,            ///< 24-bit depth.
+        RGBA_4444,
+        RGBA_5551,
+        RGBA_8888,
+        RGBx_8888           ///< 32-bit depth, alpha data ignored.
+    };
+
+    typedef Vector2ui Size;
+
+    /// GL format + type for glTex(Sub)Image.
+    struct GLFormat {
+        duint format;
+        duint type;
+        duint rowAlignment;
+
+        GLFormat(duint f, duint t, duint ra) : format(f), type(t), rowAlignment(ra) {}
+    };
+
+public:
+    Image();
+    Image(Image const &other);
+    Image(QImage const &image);
+
+    /**
+     * Constructs an image, taking a copy of the pixel data.
+     *
+     * @param size    Size of the image.
+     * @param format  Data format.
+     * @param pixels  Pixel data.
+     */
+    Image(Size const &size, Format format, IByteArray const &pixels);
+
+    Image(Size const &size, Format format, ByteRefArray const &refPixels);
+
+    Image &operator = (Image const &other);
+    Image &operator = (QImage const &other);
+
+    Format format() const;
+
+    QImage::Format qtFormat() const;
+
+    Size size() const;
+
+    /**
+     * Number of bits per pixel.
+     */
+    int depth() const;
+
+    /**
+     * Number of bytes between rows in the pixel data.
+     */
+    int stride() const;
+
+    /**
+     * Total number of bytes in the pixel data.
+     */
+    int byteCount() const;
+
+    void const *bits() const;
+
+    void *bits();
+
+    /**
+     * Determines if the image format can be uploaded to OpenGL without
+     * conversion of any kind.
+     */
+    bool isGLCompatible() const;
+
+    bool canConvertToQImage() const;
+
+    /**
+     * Converts the image to a QImage. Only allowed if canConvertToQImage()
+     * returns @c true.
+     *
+     * @return QImage instance.
+     */
+    QImage toQImage() const;
+
+    GLFormat glFormat() const;
+
+public:
+    static GLFormat glFormat(Format imageFormat);
+    static GLFormat glFormat(QImage::Format qtImageFormat);
+
+private:
+    DENG2_PRIVATE(d)
+};
+
+} // namespace de
+
+#endif // LIBGUI_IMAGE_H

doomsday/libgui/libgui.pro

@@ -58,6 +58,7 @@ HEADERS += \
     include/de/GLTexture \
     include/de/GLUniform \
     include/de/GuiApp \
+    include/de/Image \
     include/de/KeyEvent \
     include/de/KeyEventSource \
     include/de/MouseEventSource \
@@ -78,6 +79,7 @@ HEADERS += \
     include/de/gui/gltexture.h \
     include/de/gui/gluniform.h \
     include/de/gui/guiapp.h \
+    include/de/gui/image.h \
     include/de/gui/keyevent.h \
     include/de/gui/keyeventsource.h \
     include/de/gui/libgui.h \
@@ -99,6 +101,7 @@ SOURCES += \
     src/gltexture.cpp \
     src/gluniform.cpp \
     src/guiapp.cpp \
+    src/image.cpp \
     src/keyevent.cpp \
     src/persistentcanvaswindow.cpp \
     src/glentrypoints.cpp