src/hbcore/ovgeffects/hbvgmaskeffect.cpp
changeset 0 16d8024aca5e
child 5 627c4a0fd0e7
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hbcore/ovgeffects/hbvgmaskeffect.cpp	Mon Apr 19 14:02:13 2010 +0300
@@ -0,0 +1,304 @@
+/****************************************************************************
+**
+** Copyright (C) 2008-2010 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (developer.feedback@nokia.com)
+**
+** This file is part of the HbCore module of the UI Extensions for Mobile.
+**
+** GNU Lesser General Public License Usage
+** This file may be used under the terms of the GNU Lesser General Public
+** License version 2.1 as published by the Free Software Foundation and
+** appearing in the file LICENSE.LGPL included in the packaging of this file.
+** Please review the following information to ensure the GNU Lesser General
+** Public License version 2.1 requirements will be met:
+** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at developer.feedback@nokia.com.
+**
+****************************************************************************/
+
+#include "hbvgmaskeffect_p.h"
+#include "hbvgmaskeffect_p_p.h"
+#include <QPainter>
+#include <QPaintEngine>
+#include <QPaintDevice>
+
+/*!
+ * \class HbVgMaskEffect
+ *
+ * \brief OpenVG-based mask effect.
+ *
+ * The mask effect can be used to make a rectangular area or an area
+ * defined by a pixmap's alpha channel transparent. The opacity effect
+ * parameter is ignored.
+ *
+ * \internal
+ */
+
+HbVgMaskEffectPrivate::HbVgMaskEffectPrivate()
+    : maskRectIsInDeviceCoords(false), maskCallback(0)
+{
+}
+
+HbVgMaskEffect::HbVgMaskEffect(QObject *parent)
+    : HbVgEffect(*new HbVgMaskEffectPrivate, parent)
+{
+}
+
+HbVgMaskEffect::HbVgMaskEffect(HbVgMaskEffectPrivate &dd, QObject *parent)
+    : HbVgEffect(dd, parent)
+{
+}
+
+HbVgMaskEffect::~HbVgMaskEffect()
+{
+}
+
+/*!
+ * Turns off masking. Any previously set mask pixmap or rectangle will not be
+ * effective anymore.
+ */
+void HbVgMaskEffect::clear()
+{
+    Q_D(HbVgMaskEffect);
+    d->mask = d->scaledMask = d->callbackResult = QPixmap();
+    d->maskRect = QRectF();
+    d->maskRectIsInDeviceCoords = false;
+    d->maskCallback = 0;
+    d->maskCallbackParam = 0;
+}
+
+/*!
+ * Returns the mask pixmap set by the previous setMask() call.
+ */
+QPixmap HbVgMaskEffect::mask() const
+{
+    Q_D(const HbVgMaskEffect);
+    return d->mask;
+}
+
+/*!
+ * Returns the scaled version of the mask that was used during the previous
+ * paint. Will return a null pixmap if no painting took place since the last
+ * setMask() call.
+ */
+QPixmap HbVgMaskEffect::scaledMask() const
+{
+    Q_D(const HbVgMaskEffect);
+    return d->scaledMask;
+}
+
+/*!
+ * Sets the mask pixmap. Only the alpha channel is relevant. Pixels where alpha
+ * is 0 will be set transparent. The pixmap is subject to scaling and therefore
+ * distortion may occur. If this is not acceptable then use the callback
+ * version. Any previously set mask pixmap or rectangle will not be effective
+ * anymore.
+ */
+void HbVgMaskEffect::setMask(const QPixmap &mask)
+{
+    Q_D(HbVgMaskEffect);
+    clear();
+    d->mask = mask;
+    updateEffect();
+    emit maskChanged(mask);
+}
+
+/*!
+ * Returns the currently set mask callback pointer.
+ */
+HbVgMaskEffect::MaskCallback HbVgMaskEffect::maskCallback() const
+{
+    Q_D(const HbVgMaskEffect);
+    return d->maskCallback;
+}
+
+/*!
+ * Returns the currently set custom parameter that will be passed to the
+ * callback.
+ */
+void *HbVgMaskEffect::maskCallbackParam() const
+{
+    Q_D(const HbVgMaskEffect);
+    return d->maskCallbackParam;
+}
+
+/*!
+ * If the user of the API is able to generate a mask pixmap for a given size,
+ * use this function instead of setMask(). The callback will be invoked during
+ * painting to get the mask pixmap. It should return a pixmap that has a size
+ * that is same as the size that has been passed to the callback. The effect
+ * tries to reduce the number of calls by calling only when a new callback is
+ * set or when the size of the source item is different than before. Any
+ * previously set mask pixmap or rectangle will not be effective anymore.
+ */
+void HbVgMaskEffect::setMaskCallback(MaskCallback callback, void *param)
+{
+    Q_D(HbVgMaskEffect);
+    if (d->maskCallback == callback)
+        return;
+    clear();
+    d->maskCallback = callback;
+    d->maskCallbackParam = param;
+    updateEffect();
+    emit maskCallbackChanged(callback);
+}
+
+/*!
+ * Returns the mask rectangle set by the previous setMaskRect() call.
+ */
+QRectF HbVgMaskEffect::maskRect() const
+{
+    Q_D(const HbVgMaskEffect);
+    return d->maskRectIsInDeviceCoords ? QRectF() : d->maskRect;
+}
+
+/*!
+ * Returns the mask rectangle set by the previous setMaskDeviceRect() call.
+ */
+QRectF HbVgMaskEffect::maskDeviceRect() const
+{
+    Q_D(const HbVgMaskEffect);
+    return d->maskRectIsInDeviceCoords ? d->maskRect : QRectF();
+}
+
+/*!
+ * Sets the mask rectangle. The area defined by the rectangle will be made
+ * transparent inside the source item. Any previously set mask pixmap or
+ * rectangle will not be effective anymore.
+ */
+void HbVgMaskEffect::setMaskRect(const QRectF &rect)
+{
+    Q_D(HbVgMaskEffect);
+    if (rect == d->maskRect && !d->maskRectIsInDeviceCoords)
+        return;
+    clear();
+    d->maskRect = rect;
+    d->maskRectIsInDeviceCoords = false;
+    updateEffect();
+    emit maskRectChanged(rect);
+}
+
+/*!
+ * Similar to setMask() but the rectangle is assumed to be in device coordinates
+ * (i.e. relative to the entire screen instead of the source item), meaning that
+ * the source item will be clipped where it intersects with \a rect.
+ */
+void HbVgMaskEffect::setMaskDeviceRect(const QRectF &rect)
+{
+    Q_D(HbVgMaskEffect);
+    if (rect == d->maskRect && d->maskRectIsInDeviceCoords)
+        return;
+    clear();
+    d->maskRect = rect;
+    d->maskRectIsInDeviceCoords = true;
+    updateEffect();
+    emit maskRectChanged(rect);
+}
+
+/*!
+ * \reimp
+ */
+QRectF HbVgMaskEffect::boundingRectFor(const QRectF &rect) const
+{
+    return rect;
+}
+
+/*!
+ * Returns the OpenVG Y coordinate for a rectangle with the given Qt Y
+ * coordinate and height.
+ *
+ * \internal
+ */
+inline int toVgYH(int y, int h, QPaintDevice *pdev)
+{
+    return pdev->height() - 1 - y - h;
+}
+
+/*!
+ * \reimp
+ */
+void HbVgMaskEffect::performEffect(QPainter *painter,
+                                   const QPointF &offset,
+                                   const QVariant &vgImage,
+                                   const QSize &vgImageSize)
+{
+#ifdef HB_EFFECTS_OPENVG
+    Q_UNUSED(vgImage);
+    Q_D(HbVgMaskEffect);
+
+    // Initialize scaledMask if the mask has changed or the size of the source
+    // is different than before.
+    if (!d->mask.isNull()) {
+        if (d->scaledMask.isNull())
+            d->scaledMask = d->mask;
+        // Scale only when really needed, i.e. when the size is different than
+        // before (or there is a new mask).
+        if (d->scaledMask.size() != vgImageSize)
+            d->scaledMask = d->mask.scaled(vgImageSize);
+    }
+
+    vgSeti(VG_MASKING, VG_TRUE);
+    QPaintDevice *pdev = painter->paintEngine()->paintDevice();
+    // Set the mask for the entire surface to 1 (i.e. nothing is transparent).
+    vgMask(VG_INVALID_HANDLE, VG_FILL_MASK,
+           0, 0, pdev->width(), pdev->height());
+
+    // If there is a pixmap then use that, otherwise use the rectangle. If none
+    // of these is set then try the callback, if that is not set either then
+    // just draw the source normally.
+    QPixmap *maskPtr = 0;
+    int ox = (int) offset.x();
+    int oy = (int) offset.y();
+    if (d->scaledMask.isNull() && !d->maskRect.isNull()) {
+        int x1 = (int) d->maskRect.x();
+        int y1 = (int) d->maskRect.y();
+        int w = (int) d->maskRect.width();
+        int h = (int) d->maskRect.height();
+        if (!d->maskRectIsInDeviceCoords) {
+            x1 += ox;
+            y1 += oy;
+        }
+        // Make the area defined by the rectangle transparent. Passing
+        // VG_CLEAR_MASK results in writing 0 to the mask which results in
+        // transparent pixels at that position.
+        vgMask(VG_INVALID_HANDLE, VG_CLEAR_MASK,
+               x1, toVgYH(y1, h, pdev),
+               w, h);
+    } else if (!d->scaledMask.isNull()) {
+        maskPtr = &d->scaledMask;
+    } else if (d->maskCallback) {
+        // Invoke the callback but only if it has just been set or the size of
+        // the source is different than before.
+        if (d->callbackResult.isNull() || d->callbackResult.size() != vgImageSize)
+            d->callbackResult = d->maskCallback(vgImageSize, d->maskCallbackParam);
+        maskPtr = &d->callbackResult;
+    }
+
+    if (maskPtr) {
+        int w = vgImageSize.width();
+        int h = vgImageSize.height();
+        // Will use the alpha channel from the image, alpha=0 => 0 in the mask
+        // => transparent pixel, alpha=255 => 1 in the mask => opaque pixel.
+        vgMask(qPixmapToVGImage(*maskPtr), VG_SET_MASK,
+               ox, toVgYH(oy, h, pdev),
+               w, h);
+    }
+
+    // Draw the source item with masking enabled.
+    painter->drawPixmap(offset, d->srcPixmap);
+    vgSeti(VG_MASKING, VG_FALSE);
+
+#else
+    Q_UNUSED(painter);
+    Q_UNUSED(offset);
+    Q_UNUSED(vgImage);
+    Q_UNUSED(vgImageSize);
+#endif
+}