1 files changed, 132 insertions, 0 deletions
diff --git a/chalk/core/kis_alpha_mask.cpp b/chalk/core/kis_alpha_mask.cpp
new file mode 100644
index 00000000..15296308
--- /dev/null
+++ b/chalk/core/kis_alpha_mask.cpp
@@ -0,0 +1,132 @@
+/*
+ *  Copyright (c) 2004 Boudewijn Rempt <[email protected]>
+ *
+ *  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, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+#include <cfloat>
+#include <tqimage.h>
+#include <tqvaluevector.h>
+
+#include <kdebug.h>
+
+#include "kis_global.h"
+#include "kis_alpha_mask.h"
+
+KisAlphaMask::KisAlphaMask(const TQImage& img, bool hasColor)
+{
+    m_width = img.width();
+    m_height = img.height();
+
+    if (hasColor) {
+        copyAlpha(img);
+    }
+    else {
+        computeAlpha(img);
+    }
+}
+
+KisAlphaMask::KisAlphaMask(const TQImage& img)
+{
+    m_width = img.width();
+    m_height = img.height();
+
+    if (!img.allGray()) {
+        copyAlpha(img);
+    }
+    else {
+        computeAlpha(img);
+    }
+}
+
+KisAlphaMask::KisAlphaMask(TQ_INT32 width, TQ_INT32 height)
+{
+    m_width = width;
+    m_height = height;
+
+    m_data.resize(width * height, OPACITY_TRANSPARENT);
+}
+
+KisAlphaMask::~KisAlphaMask()
+{
+}
+
+TQ_INT32 KisAlphaMask::width() const
+{
+    return m_width;
+}
+
+TQ_INT32 KisAlphaMask::height() const
+{
+    return m_height;
+}
+
+void KisAlphaMask::setAlphaAt(TQ_INT32 x, TQ_INT32 y, TQ_UINT8 alpha)
+{
+    if (y >= 0 && y < m_height && x >= 0 && x < m_width) {
+        m_data[(y * m_width) + x] = alpha;
+    }
+}
+
+void KisAlphaMask::copyAlpha(const TQImage& img)
+{
+    for (int y = 0; y < img.height(); y++) {
+        for (int x = 0; x < img.width(); x++) {
+                        TQRgb c = img.pixel(x,y);
+                        TQ_UINT8 a = (tqGray(c) * tqAlpha(c)) / 255;
+            m_data.push_back(a);
+
+        }
+    }
+}
+
+void KisAlphaMask::computeAlpha(const TQImage& img)
+{
+    // The brushes are mostly grayscale on a white background,
+    // although some do have a colors. The alpha channel is seldom
+    // used, so we take the average gray value of this pixel of
+    // the brush as the setting for the opacitiy. We need to
+    // invert it, because 255, 255, 255 is white, which is
+    // completely transparent, but 255 corresponds to
+    // OPACITY_OPAQUE.
+
+    for (int y = 0; y < img.height(); y++) {
+        for (int x = 0; x < img.width(); x++) {
+            m_data.push_back(255 - tqRed(img.pixel(x, y)));
+        }
+    }
+}
+
+KisAlphaMaskSP KisAlphaMask::interpolate(KisAlphaMaskSP mask1, KisAlphaMaskSP mask2, double t)
+{
+    Q_ASSERT((mask1->width() == mask2->width()) && (mask1->height() == mask2->height()));
+    Q_ASSERT(t > -DBL_EPSILON && t < 1 + DBL_EPSILON);
+
+    int width = mask1->width();
+    int height = mask1->height();
+    KisAlphaMaskSP outputMask = new KisAlphaMask(width, height);
+    TQ_CHECK_PTR(outputMask);
+
+    for (int x = 0; x < width; x++) {
+        for (int y = 0; y < height; y++) {
+            TQ_UINT8 d = static_cast<TQ_UINT8>((1 - t) * mask1->alphaAt(x, y) + t * mask2->alphaAt(x, y));
+            outputMask->setAlphaAt(x, y, d);
+        }
+    }
+
+    return outputMask;
+}
+
+