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koffice/chalk/core/kis_alpha_mask.cc

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/*
* Copyright (c) 2004 Boudewijn Rempt <boud@valdyas.org>
*
* 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);
Q_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;
}