xcf.cpp
/*
* qxcfi.cpp: A Qt 3 plug-in for reading GIMP XCF image files
* Copyright (C) 2001 lignum Computing, Inc. <allen@lignumcomputing.com>
* Copyright (C) 2004 Melchior FRANZ <mfranz@kde.org>
*
* This plug-in is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include <stdlib.h>
#include <qimage.h>
#include <qiodevice.h>
#include <qvaluestack.h>
#include <qvaluevector.h>
#include <kdebug.h>
#include "xcf.h"
KDE_EXPORT void kimgio_xcf_read(QImageIO *io)
{
XCFImageFormat xcfif;
xcfif.readXCF(io);
}
KDE_EXPORT void kimgio_xcf_write(QImageIO *io)
{
kdDebug(399) << "XCF: write support not implemented" << endl;
io->setStatus(-1);
}
int XCFImageFormat::random_table[RANDOM_TABLE_SIZE];
//int XCFImageFormat::add_lut[256][256];
const XCFImageFormat::LayerModes XCFImageFormat::layer_modes[] = {
{true}, // NORMAL_MODE
{true}, // DISSOLVE_MODE
{true}, // BEHIND_MODE
{false}, // MULTIPLY_MODE
{false}, // SCREEN_MODE
{false}, // OVERLAY_MODE
{false}, // DIFFERENCE_MODE
{false}, // ADDITION_MODE
{false}, // SUBTRACT_MODE
{false}, // DARKEN_ONLY_MODE
{false}, // LIGHTEN_ONLY_MODE
{false}, // HUE_MODE
{false}, // SATURATION_MODE
{false}, // COLOR_MODE
{false}, // VALUE_MODE
{false}, // DIVIDE_MODE
{true}, // ERASE_MODE
{true}, // REPLACE_MODE
{true}, // ANTI_ERASE_MODE
};
inline QRgb qRgba ( QRgb rgb, int a )
{
return ((a & 0xff) << 24 | (rgb & RGB_MASK));
}
XCFImageFormat::XCFImageFormat()
{
// From GIMP "paint_funcs.c" v1.2
srand(RANDOM_SEED);
for (int i = 0; i < RANDOM_TABLE_SIZE; i++)
random_table[i] = rand();
for (int i = 0; i < RANDOM_TABLE_SIZE; i++) {
int tmp;
int swap = i + rand() % (RANDOM_TABLE_SIZE - i);
tmp = random_table[i];
random_table[i] = random_table[swap];
random_table[swap] = tmp;
}
// for (int j = 0; j < 256; j++) {
// for (int k = 0; k < 256; k++) {
// int tmp_sum = j + k;
// if (tmp_sum > 255)
// tmp_sum = 255;
// add_lut[j][k] = tmp_sum;
// }
// }
}
inline
int XCFImageFormat::add_lut( int a, int b ) {
return QMIN( a + b, 255 );
}
void XCFImageFormat::readXCF(QImageIO *io)
{
XCFImage xcf_image;
QDataStream xcf_io(io->ioDevice());
char tag[14];
xcf_io.readRawBytes(tag, sizeof(tag));
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on header tag" << endl;
return;
}
xcf_io >> xcf_image.width >> xcf_image.height >> xcf_image.type;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on image info" << endl;
return;
}
kdDebug() << tag << " " << xcf_image.width << " " << xcf_image.height << " " << xcf_image.type << endl;
if (!loadImageProperties(xcf_io, xcf_image))
return;
// The layers appear to be stored in top-to-bottom order. This is
// the reverse of how a merged image must be computed. So, the layer
// offsets are pushed onto a LIFO stack (thus, we don't have to load
// all the data of all layers before beginning to construct the
// merged image).
QValueStack<Q_INT32> layer_offsets;
while (true) {
Q_INT32 layer_offset;
xcf_io >> layer_offset;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer offsets" << endl;
return;
}
if (layer_offset == 0)
break;
layer_offsets.push(layer_offset);
}
xcf_image.num_layers = layer_offsets.size();
if (layer_offsets.size() == 0) {
kdDebug(399) << "XCF: no layers!" << endl;
return;
}
// Load each layer and add it to the image
while (!layer_offsets.isEmpty()) {
Q_INT32 layer_offset = layer_offsets.pop();
xcf_io.device()->at(layer_offset);
if (!loadLayer(xcf_io, xcf_image))
return;
}
if (!xcf_image.initialized) {
kdDebug(399) << "XCF: no visible layers!" << endl;
return;
}
io->setImage(xcf_image.image);
io->setStatus(0);
}
bool XCFImageFormat::loadImageProperties(QDataStream& xcf_io, XCFImage& xcf_image)
{
while (true) {
PropType type;
QByteArray bytes;
if (!loadProperty(xcf_io, type, bytes)) {
kdDebug(399) << "XCF: error loading global image properties" << endl;
return false;
}
QDataStream property(bytes, IO_ReadOnly);
switch (type) {
case PROP_END:
return true;
case PROP_COMPRESSION:
property >> xcf_image.compression;
break;
case PROP_RESOLUTION:
property >> xcf_image.x_resolution >> xcf_image.y_resolution;
break;
case PROP_TATTOO:
property >> xcf_image.tattoo;
break;
case PROP_PARASITES:
while (!property.atEnd()) {
char* tag;
Q_UINT32 size;
property.readBytes(tag, size);
Q_UINT32 flags;
char* data=0;
property >> flags >> data;
if (tag && strncmp(tag, "gimp-comment", strlen("gimp-comment")) == 0)
xcf_image.image.setText("Comment", 0, data);
delete[] tag;
delete[] data;
}
break;
case PROP_UNIT:
property >> xcf_image.unit;
break;
case PROP_PATHS: // This property is ignored.
break;
case PROP_USER_UNIT: // This property is ignored.
break;
case PROP_COLORMAP:
property >> xcf_image.num_colors;
if(xcf_image.num_colors < 0 || xcf_image.num_colors > 65535)
return false;
xcf_image.palette.reserve(xcf_image.num_colors);
for (int i = 0; i < xcf_image.num_colors; i++) {
uchar r, g, b;
property >> r >> g >> b;
xcf_image.palette.push_back( qRgb(r,g,b) );
}
break;
default:
kdDebug(399) << "XCF: unimplemented image property" << type
<< ", size " << bytes.size() << endl;
}
}
}
bool XCFImageFormat::loadProperty(QDataStream& xcf_io, PropType& type, QByteArray& bytes)
{
Q_UINT32 foo;
xcf_io >> foo;
type=PropType(foo); // TODO urks
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on property type" << type << endl;
return false;
}
char* data;
Q_UINT32 size;
// The colormap property size is not the correct number of bytes:
// The GIMP source xcf.c has size = 4 + ncolors, but it should be
// 4 + 3 * ncolors
if (type == PROP_COLORMAP) {
xcf_io >> size;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on property " << type << " size" << endl;
return false;
}
if(size > 65535 || size < 4)
return false;
size = 3 * (size - 4) + 4;
data = new char[size];
xcf_io.readRawBytes(data, size);
} else if (type == PROP_USER_UNIT) {
// The USER UNIT property size is not correct. I'm not sure why, though.
float factor;
Q_INT32 digits;
char* unit_strings;
xcf_io >> size >> factor >> digits;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on property " << type << endl;
return false;
}
for (int i = 0; i < 5; i++) {
xcf_io >> unit_strings;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on property " << type << endl;
return false;
}
delete[] unit_strings;
}
size = 0;
} else {
xcf_io >> size;
if(size >256000)
return false;
data = new char[size];
xcf_io.readRawBytes(data, size);
}
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on property " << type << " data, size " << size << endl;
return false;
}
if (size != 0 && data) {
bytes.assign(data,size);
}
return true;
}
bool XCFImageFormat::loadLayer(QDataStream& xcf_io, XCFImage& xcf_image)
{
Layer& layer(xcf_image.layer);
delete[] layer.name;
xcf_io >> layer.width >> layer.height >> layer.type >> layer.name;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer" << endl;
return false;
}
if (!loadLayerProperties(xcf_io, layer))
return false;
#if 0
cout << "layer: \"" << layer.name << "\", size: " << layer.width << " x "
<< layer.height << ", type: " << layer.type << ", mode: " << layer.mode
<< ", opacity: " << layer.opacity << ", visible: " << layer.visible
<< ", offset: " << layer.x_offset << ", " << layer.y_offset << endl;
#endif
// Skip reading the rest of it if it is not visible. Typically, when
// you export an image from the The GIMP it flattens (or merges) only
// the visible layers into the output image.
if (layer.visible == 0)
return true;
// If there are any more layers, merge them into the final QImage.
xcf_io >> layer.hierarchy_offset >> layer.mask_offset;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer image offsets" << endl;
return false;
}
// Allocate the individual tile QImages based on the size and type
// of this layer.
if( !composeTiles(xcf_image))
return false;
xcf_io.device()->at(layer.hierarchy_offset);
// As tiles are loaded, they are copied into the layers tiles by
// this routine. (loadMask(), below, uses a slightly different
// version of assignBytes().)
layer.assignBytes = assignImageBytes;
if (!loadHierarchy(xcf_io, layer))
return false;
if (layer.mask_offset != 0) {
xcf_io.device()->at(layer.mask_offset);
if (!loadMask(xcf_io, layer))
return false;
}
// Now we should have enough information to initialize the final
// QImage. The first visible layer determines the attributes
// of the QImage.
if (!xcf_image.initialized) {
if( !initializeImage(xcf_image))
return false;
copyLayerToImage(xcf_image);
xcf_image.initialized = true;
} else
mergeLayerIntoImage(xcf_image);
return true;
}
bool XCFImageFormat::loadLayerProperties(QDataStream& xcf_io, Layer& layer)
{
while (true) {
PropType type;
QByteArray bytes;
if (!loadProperty(xcf_io, type, bytes)) {
kdDebug(399) << "XCF: error loading layer properties" << endl;
return false;
}
QDataStream property(bytes, IO_ReadOnly);
switch (type) {
case PROP_END:
return true;
case PROP_ACTIVE_LAYER:
layer.active = true;
break;
case PROP_OPACITY:
property >> layer.opacity;
break;
case PROP_VISIBLE:
property >> layer.visible;
break;
case PROP_LINKED:
property >> layer.linked;
break;
case PROP_PRESERVE_TRANSPARENCY:
property >> layer.preserve_transparency;
break;
case PROP_APPLY_MASK:
property >> layer.apply_mask;
break;
case PROP_EDIT_MASK:
property >> layer.edit_mask;
break;
case PROP_SHOW_MASK:
property >> layer.show_mask;
break;
case PROP_OFFSETS:
property >> layer.x_offset >> layer.y_offset;
break;
case PROP_MODE:
property >> layer.mode;
break;
case PROP_TATTOO:
property >> layer.tattoo;
break;
default:
kdDebug(399) << "XCF: unimplemented layer property " << type
<< ", size " << bytes.size() << endl;
}
}
}
bool XCFImageFormat::composeTiles(XCFImage& xcf_image)
{
Layer& layer(xcf_image.layer);
layer.nrows = (layer.height + TILE_HEIGHT - 1) / TILE_HEIGHT;
layer.ncols = (layer.width + TILE_WIDTH - 1) / TILE_WIDTH;
layer.image_tiles.resize(layer.nrows);
if (layer.type == GRAYA_GIMAGE || layer.type == INDEXEDA_GIMAGE)
layer.alpha_tiles.resize(layer.nrows);
if (layer.mask_offset != 0)
layer.mask_tiles.resize(layer.nrows);
for (uint j = 0; j < layer.nrows; j++) {
layer.image_tiles[j].resize(layer.ncols);
if (layer.type == GRAYA_GIMAGE || layer.type == INDEXEDA_GIMAGE)
layer.alpha_tiles[j].resize(layer.ncols);
if (layer.mask_offset != 0)
layer.mask_tiles[j].resize(layer.ncols);
}
for (uint j = 0; j < layer.nrows; j++) {
for (uint i = 0; i < layer.ncols; i++) {
uint tile_width = (i + 1) * TILE_WIDTH <= layer.width
? TILE_WIDTH : layer.width - i * TILE_WIDTH;
uint tile_height = (j + 1) * TILE_HEIGHT <= layer.height
? TILE_HEIGHT : layer.height - j * TILE_HEIGHT;
// Try to create the most appropriate QImage (each GIMP layer
// type is treated slightly differently)
switch (layer.type) {
case RGB_GIMAGE:
layer.image_tiles[j][i] = QImage(tile_width, tile_height, 32, 0);
if( layer.image_tiles[j][i].isNull())
return false;
layer.image_tiles[j][i].setAlphaBuffer(false);
break;
case RGBA_GIMAGE:
layer.image_tiles[j][i] = QImage(tile_width, tile_height, 32, 0);
if( layer.image_tiles[j][i].isNull())
return false;
layer.image_tiles[j][i].setAlphaBuffer(true);
break;
case GRAY_GIMAGE:
layer.image_tiles[j][i] = QImage(tile_width, tile_height, 8, 256);
if( layer.image_tiles[j][i].isNull())
return false;
setGrayPalette(layer.image_tiles[j][i]);
break;
case GRAYA_GIMAGE:
layer.image_tiles[j][i] = QImage(tile_width, tile_height, 8, 256);
if( layer.image_tiles[j][i].isNull())
return false;
setGrayPalette(layer.image_tiles[j][i]);
layer.alpha_tiles[j][i] = QImage( tile_width, tile_height, 8, 256);
if( layer.alpha_tiles[j][i].isNull())
return false;
setGrayPalette(layer.alpha_tiles[j][i]);
break;
case INDEXED_GIMAGE:
layer.image_tiles[j][i] = QImage(tile_width, tile_height, 8,
xcf_image.num_colors);
if( layer.image_tiles[j][i].isNull())
return false;
setPalette(xcf_image, layer.image_tiles[j][i]);
break;
case INDEXEDA_GIMAGE:
layer.image_tiles[j][i] = QImage(tile_width, tile_height,8,
xcf_image.num_colors);
if( layer.image_tiles[j][i].isNull())
return false;
setPalette(xcf_image, layer.image_tiles[j][i]);
layer.alpha_tiles[j][i] = QImage(tile_width, tile_height, 8, 256);
if( layer.alpha_tiles[j][i].isNull())
return false;
setGrayPalette(layer.alpha_tiles[j][i]);
}
if (layer.mask_offset != 0) {
layer.mask_tiles[j][i] = QImage(tile_width, tile_height, 8, 256);
if( layer.mask_tiles[j][i].isNull())
return false;
setGrayPalette(layer.mask_tiles[j][i]);
}
}
}
return true;
}
void XCFImageFormat::setGrayPalette(QImage& image)
{
for (int i = 0; i < 256; i++)
image.setColor(i, qRgb(i, i, i));
}
void XCFImageFormat::setPalette(XCFImage& xcf_image, QImage& image)
{
for (int i = 0; i < xcf_image.num_colors; i++)
image.setColor(i, xcf_image.palette[i]);
}
void XCFImageFormat::assignImageBytes(Layer& layer, uint i, uint j)
{
uchar* tile = layer.tile;
switch (layer.type) {
case RGB_GIMAGE:
for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
layer.image_tiles[j][i].setPixel(k, l,
qRgb(tile[0], tile[1], tile[2]));
tile += sizeof(QRgb);
}
}
break;
case RGBA_GIMAGE:
for ( int l = 0; l < layer.image_tiles[j][i].height(); l++ ) {
for ( int k = 0; k < layer.image_tiles[j][i].width(); k++ ) {
layer.image_tiles[j][i].setPixel(k, l,
qRgba(tile[0], tile[1], tile[2], tile[3]));
tile += sizeof(QRgb);
}
}
break;
case GRAY_GIMAGE:
case INDEXED_GIMAGE:
for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
layer.image_tiles[j][i].setPixel(k, l, tile[0]);
tile += sizeof(QRgb);
}
}
break;
case GRAYA_GIMAGE:
case INDEXEDA_GIMAGE:
for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
// The "if" here should not be necessary, but apparently there
// are some cases where the image can contain larger indices
// than there are colors in the palette. (A bug in The GIMP?)
if (tile[0] < layer.image_tiles[j][i].numColors())
layer.image_tiles[j][i].setPixel(k, l, tile[0]);
layer.alpha_tiles[j][i].setPixel(k, l, tile[1]);
tile += sizeof(QRgb);
}
}
break;
}
}
bool XCFImageFormat::loadHierarchy(QDataStream& xcf_io, Layer& layer)
{
Q_INT32 width;
Q_INT32 height;
Q_INT32 bpp;
Q_UINT32 offset;
xcf_io >> width >> height >> bpp >> offset;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer " << layer.name << " image header" << endl;
return false;
}
// GIMP stores images in a "mipmap"-like format (multiple levels of
// increasingly lower resolution). Only the top level is used here,
// however.
Q_UINT32 junk;
do {
xcf_io >> junk;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer " << layer.name << " level offsets" << endl;
return false;
}
} while (junk != 0);
QIODevice::Offset saved_pos = xcf_io.device()->at();
xcf_io.device()->at(offset);
if (!loadLevel(xcf_io, layer, bpp))
return false;
xcf_io.device()->at(saved_pos);
return true;
}
bool XCFImageFormat::loadLevel(QDataStream& xcf_io, Layer& layer, Q_INT32 bpp)
{
Q_INT32 width;
Q_INT32 height;
Q_UINT32 offset;
xcf_io >> width >> height >> offset;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer " << layer.name << " level info" << endl;
return false;
}
if (offset == 0)
return true;
for (uint j = 0; j < layer.nrows; j++) {
for (uint i = 0; i < layer.ncols; i++) {
if (offset == 0) {
kdDebug(399) << "XCF: incorrect number of tiles in layer " << layer.name << endl;
return false;
}
QIODevice::Offset saved_pos = xcf_io.device()->at();
Q_UINT32 offset2;
xcf_io >> offset2;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer " << layer.name << " level offset look-ahead" << endl;
return false;
}
// Evidently, RLE can occasionally expand a tile instead of compressing it!
if (offset2 == 0)
offset2 = offset + (uint)(TILE_WIDTH * TILE_HEIGHT * 4 * 1.5);
xcf_io.device()->at(offset);
int size = layer.image_tiles[j][i].width() * layer.image_tiles[j][i].height();
if (!loadTileRLE(xcf_io, layer.tile, size, offset2 - offset, bpp))
return false;
// The bytes in the layer tile are juggled differently depending on
// the target QImage. The caller has set layer.assignBytes to the
// appropriate routine.
layer.assignBytes(layer, i, j);
xcf_io.device()->at(saved_pos);
xcf_io >> offset;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on layer " << layer.name << " level offset" << endl;
return false;
}
}
}
return true;
}
bool XCFImageFormat::loadMask(QDataStream& xcf_io, Layer& layer)
{
Q_INT32 width;
Q_INT32 height;
char* name;
xcf_io >> width >> height >> name;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on mask info" << endl;
return false;
}
delete name;
if (!loadChannelProperties(xcf_io, layer))
return false;
Q_UINT32 hierarchy_offset;
xcf_io >> hierarchy_offset;
if (xcf_io.device()->status() != IO_Ok) {
kdDebug(399) << "XCF: read failure on mask image offset" << endl;
return false;
}
xcf_io.device()->at(hierarchy_offset);
layer.assignBytes = assignMaskBytes;
if (!loadHierarchy(xcf_io, layer))
return false;
return true;
}
bool XCFImageFormat::loadTileRLE(QDataStream& xcf_io, uchar* tile, int image_size,
int data_length, Q_INT32 bpp)
{
uchar* data;
uchar* xcfdata;
uchar* xcfodata;
uchar* xcfdatalimit;
xcfdata = xcfodata = new uchar[data_length];
xcf_io.readRawBytes((char*)xcfdata, data_length);
if (xcf_io.device()->status() != IO_Ok) {
delete[] xcfodata;
kdDebug(399) << "XCF: read failure on tile" << endl;
return false;
}
xcfdatalimit = &xcfodata[data_length - 1];
for (int i = 0; i < bpp; ++i) {
data = tile + i;
int count = 0;
int size = image_size;
while (size > 0) {
if (xcfdata > xcfdatalimit)
goto bogus_rle;
uchar val = *xcfdata++;
uint length = val;
if (length >= 128) {
length = 255 - (length - 1);
if (length == 128) {
if (xcfdata >= xcfdatalimit)
goto bogus_rle;
length = (*xcfdata << 8) + xcfdata[1];
xcfdata += 2;
}
count += length;
size -= length;
if (size < 0)
goto bogus_rle;
if (&xcfdata[length - 1] > xcfdatalimit)
goto bogus_rle;
while (length-- > 0) {
*data = *xcfdata++;
data += sizeof(QRgb);
}
} else {
length += 1;
if (length == 128) {
if (xcfdata >= xcfdatalimit)
goto bogus_rle;
length = (*xcfdata << 8) + xcfdata[1];
xcfdata += 2;
}
count += length;
size -= length;
if (size < 0)
goto bogus_rle;
if (xcfdata > xcfdatalimit)
goto bogus_rle;
val = *xcfdata++;
while (length-- > 0) {
*data = val;
data += sizeof(QRgb);
}
}
}
}
delete[] xcfodata;
return true;
bogus_rle:
kdDebug(399) << "The run length encoding could not be decoded properly" << endl;
delete[] xcfodata;
return false;
}
bool XCFImageFormat::loadChannelProperties(QDataStream& xcf_io, Layer& layer)
{
while (true) {
PropType type;
QByteArray bytes;
if (!loadProperty(xcf_io, type, bytes)) {
kdDebug(399) << "XCF: error loading channel properties" << endl;
return false;
}
QDataStream property(bytes, IO_ReadOnly);
switch (type) {
case PROP_END:
return true;
case PROP_OPACITY:
property >> layer.mask_channel.opacity;
break;
case PROP_VISIBLE:
property >> layer.mask_channel.visible;
break;
case PROP_SHOW_MASKED:
property >> layer.mask_channel.show_masked;
break;
case PROP_COLOR:
property >> layer.mask_channel.red >> layer.mask_channel.green
>> layer.mask_channel.blue;
break;
case PROP_TATTOO:
property >> layer.mask_channel.tattoo;
break;
default:
kdDebug(399) << "XCF: unimplemented channel property " << type
<< ", size " << bytes.size() << endl;
}
}
}
void XCFImageFormat::assignMaskBytes(Layer& layer, uint i, uint j)
{
uchar* tile = layer.tile;
for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
layer.mask_tiles[j][i].setPixel(k, l, tile[0]);
tile += sizeof(QRgb);
}
}
}
bool XCFImageFormat::initializeImage(XCFImage& xcf_image)
{
// (Aliases to make the code look a little better.)
Layer& layer(xcf_image.layer);
QImage& image(xcf_image.image);
switch (layer.type) {
case RGB_GIMAGE:
if (layer.opacity == OPAQUE_OPACITY) {
image.create( xcf_image.width, xcf_image.height, 32);
if( image.isNull())
return false;
image.fill(qRgb(255, 255, 255));
break;
} // else, fall through to 32-bit representation
case RGBA_GIMAGE:
image.create(xcf_image.width, xcf_image.height, 32);
if( image.isNull())
return false;
image.fill(qRgba(255, 255, 255, 0));
// Turning this on prevents fill() from affecting the alpha channel,
// by the way.
image.setAlphaBuffer(true);
break;
case GRAY_GIMAGE:
if (layer.opacity == OPAQUE_OPACITY) {
image.create(xcf_image.width, xcf_image.height, 8, 256);
if( image.isNull())
return false;
setGrayPalette(image);
image.fill(255);
break;
} // else, fall through to 32-bit representation
case GRAYA_GIMAGE:
image.create(xcf_image.width, xcf_image.height, 32);
if( image.isNull())
return false;
image.fill(qRgba(255, 255, 255, 0));
image.setAlphaBuffer(true);
break;
case INDEXED_GIMAGE:
// As noted in the table above, there are quite a few combinations
// which are possible with indexed images, depending on the
// presense of transparency (note: not translucency, which is not
// supported by The GIMP for indexed images) and the number of
// individual colors.
// Note: Qt treats a bitmap with a Black and White color palette
// as a mask, so only the "on" bits are drawn, regardless of the
// order color table entries. Otherwise (i.e., at least one of the
// color table entries is not black or white), it obeys the one-
// or two-color palette. Have to ask about this...
if (xcf_image.num_colors <= 2) {
image.create(xcf_image.width, xcf_image.height,
1, xcf_image.num_colors,
QImage::LittleEndian);
if( image.isNull())
return false;
image.fill(0);
setPalette(xcf_image, image);
} else if (xcf_image.num_colors <= 256) {
image.create(xcf_image.width, xcf_image.height,
8, xcf_image.num_colors,
QImage::LittleEndian);
if( image.isNull())
return false;
image.fill(0);
setPalette(xcf_image, image);
}
break;
case INDEXEDA_GIMAGE:
if (xcf_image.num_colors == 1) {
// Plenty(!) of room to add a transparent color
xcf_image.num_colors++;
xcf_image.palette.resize(xcf_image.num_colors);
xcf_image.palette[1] = xcf_image.palette[0];
xcf_image.palette[0] = qRgba(255, 255, 255, 0);
image.create(xcf_image.width, xcf_image.height,
1, xcf_image.num_colors,
QImage::LittleEndian);
if( image.isNull())
return false;
image.fill(0);
setPalette(xcf_image, image);
image.setAlphaBuffer(true);
} else if (xcf_image.num_colors < 256) {
// Plenty of room to add a transparent color
xcf_image.num_colors++;
xcf_image.palette.resize(xcf_image.num_colors);
for (int c = xcf_image.num_colors - 1; c >= 1; c--)
xcf_image.palette[c] = xcf_image.palette[c - 1];
xcf_image.palette[0] = qRgba(255, 255, 255, 0);
image.create( xcf_image.width, xcf_image.height,
8, xcf_image.num_colors);
if( image.isNull())
return false;
image.fill(0);
setPalette(xcf_image, image);
image.setAlphaBuffer(true);
} else {
// No room for a transparent color, so this has to be promoted to
// true color. (There is no equivalent PNG representation output
// from The GIMP as of v1.2.)
image.create(xcf_image.width, xcf_image.height, 32);
if( image.isNull())
return false;
image.fill(qRgba(255, 255, 255, 0));
image.setAlphaBuffer(true);
}
break;
}
image.setDotsPerMeterX((int)(xcf_image.x_resolution * INCHESPERMETER));
image.setDotsPerMeterY((int)(xcf_image.y_resolution * INCHESPERMETER));
return true;
}
void XCFImageFormat::copyLayerToImage(XCFImage& xcf_image)
{
Layer& layer(xcf_image.layer);
QImage& image(xcf_image.image);
PixelCopyOperation copy = 0;
switch (layer.type) {
case RGB_GIMAGE:
case RGBA_GIMAGE:
copy = copyRGBToRGB;
break;
case GRAY_GIMAGE:
if (layer.opacity == OPAQUE_OPACITY)
copy = copyGrayToGray;
else
copy = copyGrayToRGB;
break;
case GRAYA_GIMAGE:
copy = copyGrayAToRGB;
break;
case INDEXED_GIMAGE:
copy = copyIndexedToIndexed;
break;
case INDEXEDA_GIMAGE:
if (xcf_image.image.depth() <= 8)
copy = copyIndexedAToIndexed;
else
copy = copyIndexedAToRGB;
}
// For each tile...
for (uint j = 0; j < layer.nrows; j++) {
uint y = j * TILE_HEIGHT;
for (uint i = 0; i < layer.ncols; i++) {
uint x = i * TILE_WIDTH;
// This seems the best place to apply the dissolve because it
// depends on the global position of each tile's
// pixels. Apparently it's the only mode which can apply to a
// single layer.
if (layer.mode == DISSOLVE_MODE) {
if (layer.type == RGBA_GIMAGE)
dissolveRGBPixels(layer.image_tiles[j][i], x, y);
else if (layer.type == GRAYA_GIMAGE)
dissolveAlphaPixels(layer.alpha_tiles[j][i], x, y);
}
for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
int m = x + k + layer.x_offset;
int n = y + l + layer.y_offset;
if (m < 0 || m >= image.width() || n < 0 || n >= image.height())
continue;
(*copy)(layer, i, j, k, l, image, m, n);
}
}
}
}
}
void XCFImageFormat::copyRGBToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
QRgb src = layer.image_tiles[j][i].pixel(k, l);
uchar src_a = layer.opacity;
if (layer.type == RGBA_GIMAGE)
src_a = INT_MULT(src_a, qAlpha(src));
// Apply the mask (if any)
if (layer.apply_mask == 1 && layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
image.setPixel(m, n, qRgba(src, src_a));
}
void XCFImageFormat::copyGrayToGray(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
int src = layer.image_tiles[j][i].pixelIndex(k, l);
image.setPixel(m, n, src);
}
void XCFImageFormat::copyGrayToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
QRgb src = layer.image_tiles[j][i].pixel(k, l);
uchar src_a = layer.opacity;
image.setPixel(m, n, qRgba(src, src_a));
}
void XCFImageFormat::copyGrayAToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
QRgb src = layer.image_tiles[j][i].pixel(k, l);
uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
src_a = INT_MULT(src_a, layer.opacity);
// Apply the mask (if any)
if (layer.apply_mask == 1 && layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
image.setPixel(m, n, qRgba(src, src_a));
}
void XCFImageFormat::copyIndexedToIndexed(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
int src = layer.image_tiles[j][i].pixelIndex(k, l);
image.setPixel(m, n, src);
}
void XCFImageFormat::copyIndexedAToIndexed(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
uchar src = layer.image_tiles[j][i].pixelIndex(k, l);
uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
src_a = INT_MULT(src_a, layer.opacity);
if (layer.apply_mask == 1 &&
layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
if (src_a > 127)
src++;
else
src = 0;
image.setPixel(m, n, src);
}
void XCFImageFormat::copyIndexedAToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
QRgb src = layer.image_tiles[j][i].pixel(k, l);
uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
src_a = INT_MULT(src_a, layer.opacity);
// Apply the mask (if any)
if (layer.apply_mask == 1 && layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
// This is what appears in the GIMP window
if (src_a <= 127)
src_a = 0;
else
src_a = OPAQUE_OPACITY;
image.setPixel(m, n, qRgba(src, src_a));
}
void XCFImageFormat::mergeLayerIntoImage(XCFImage& xcf_image)
{
Layer& layer(xcf_image.layer);
QImage& image(xcf_image.image);
PixelMergeOperation merge = 0;
switch (layer.type) {
case RGB_GIMAGE:
case RGBA_GIMAGE:
merge = mergeRGBToRGB;
break;
case GRAY_GIMAGE:
if (layer.opacity == OPAQUE_OPACITY)
merge = mergeGrayToGray;
else
merge = mergeGrayToRGB;
break;
case GRAYA_GIMAGE:
if (xcf_image.image.depth() <= 8)
merge = mergeGrayAToGray;
else
merge = mergeGrayAToRGB;
break;
case INDEXED_GIMAGE:
merge = mergeIndexedToIndexed;
break;
case INDEXEDA_GIMAGE:
if (xcf_image.image.depth() <= 8)
merge = mergeIndexedAToIndexed;
else
merge = mergeIndexedAToRGB;
}
for (uint j = 0; j < layer.nrows; j++) {
uint y = j * TILE_HEIGHT;
for (uint i = 0; i < layer.ncols; i++) {
uint x = i * TILE_WIDTH;
// This seems the best place to apply the dissolve because it
// depends on the global position of each tile's
// pixels. Apparently it's the only mode which can apply to a
// single layer.
if (layer.mode == DISSOLVE_MODE) {
if (layer.type == RGBA_GIMAGE)
dissolveRGBPixels(layer.image_tiles[j][i], x, y);
else if (layer.type == GRAYA_GIMAGE)
dissolveAlphaPixels(layer.alpha_tiles[j][i], x, y);
}
for (int l = 0; l < layer.image_tiles[j][i].height(); l++) {
for (int k = 0; k < layer.image_tiles[j][i].width(); k++) {
int m = x + k + layer.x_offset;
int n = y + l + layer.y_offset;
if (m < 0 || m >= image.width() || n < 0 || n >= image.height())
continue;
(*merge)(layer, i, j, k, l, image, m, n);
}
}
}
}
}
void XCFImageFormat::mergeRGBToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
QRgb src = layer.image_tiles[j][i].pixel(k, l);
QRgb dst = image.pixel(m, n);
uchar src_r = qRed(src);
uchar src_g = qGreen(src);
uchar src_b = qBlue(src);
uchar src_a = qAlpha(src);
uchar dst_r = qRed(dst);
uchar dst_g = qGreen(dst);
uchar dst_b = qBlue(dst);
uchar dst_a = qAlpha(dst);
switch (layer.mode) {
case MULTIPLY_MODE: {
src_r = INT_MULT(src_r, dst_r);
src_g = INT_MULT(src_g, dst_g);
src_b = INT_MULT(src_b, dst_b);
src_a = KMIN(src_a, dst_a);
}
break;
case DIVIDE_MODE: {
src_r = KMIN((dst_r * 256) / (1 + src_r), 255);
src_g = KMIN((dst_g * 256) / (1 + src_g), 255);
src_b = KMIN((dst_b * 256) / (1 + src_b), 255);
src_a = KMIN(src_a, dst_a);
}
break;
case SCREEN_MODE: {
src_r = 255 - INT_MULT(255 - dst_r, 255 - src_r);
src_g = 255 - INT_MULT(255 - dst_g, 255 - src_g);
src_b = 255 - INT_MULT(255 - dst_b, 255 - src_b);
src_a = KMIN(src_a, dst_a);
}
break;
case OVERLAY_MODE: {
src_r = INT_MULT(dst_r, dst_r + INT_MULT(2 * src_r, 255 - dst_r));
src_g = INT_MULT(dst_g, dst_g + INT_MULT(2 * src_g, 255 - dst_g));
src_b = INT_MULT(dst_b, dst_b + INT_MULT(2 * src_b, 255 - dst_b));
src_a = KMIN(src_a, dst_a);
}
break;
case DIFFERENCE_MODE: {
src_r = dst_r > src_r ? dst_r - src_r : src_r - dst_r;
src_g = dst_g > src_g ? dst_g - src_g : src_g - dst_g;
src_b = dst_b > src_b ? dst_b - src_b : src_b - dst_b;
src_a = KMIN(src_a, dst_a);
}
break;
case ADDITION_MODE: {
src_r = add_lut(dst_r,src_r);
src_g = add_lut(dst_g,src_g);
src_b = add_lut(dst_b,src_b);
src_a = KMIN(src_a, dst_a);
}
break;
case SUBTRACT_MODE: {
src_r = dst_r > src_r ? dst_r - src_r : 0;
src_g = dst_g > src_g ? dst_g - src_g : 0;
src_b = dst_b > src_b ? dst_b - src_b : 0;
src_a = KMIN(src_a, dst_a);
}
break;
case DARKEN_ONLY_MODE: {
src_r = dst_r < src_r ? dst_r : src_r;
src_g = dst_g < src_g ? dst_g : src_g;
src_b = dst_b < src_b ? dst_b : src_b;
src_a = KMIN( src_a, dst_a );
}
break;
case LIGHTEN_ONLY_MODE: {
src_r = dst_r < src_r ? src_r : dst_r;
src_g = dst_g < src_g ? src_g : dst_g;
src_b = dst_b < src_b ? src_b : dst_b;
src_a = KMIN(src_a, dst_a);
}
break;
case HUE_MODE: {
uchar new_r = dst_r;
uchar new_g = dst_g;
uchar new_b = dst_b;
RGBTOHSV(src_r, src_g, src_b);
RGBTOHSV(new_r, new_g, new_b);
new_r = src_r;
HSVTORGB(new_r, new_g, new_b);
src_r = new_r;
src_g = new_g;
src_b = new_b;
src_a = KMIN( src_a, dst_a );
}
break;
case SATURATION_MODE: {
uchar new_r = dst_r;
uchar new_g = dst_g;
uchar new_b = dst_b;
RGBTOHSV(src_r, src_g, src_b);
RGBTOHSV(new_r, new_g, new_b);
new_g = src_g;
HSVTORGB(new_r, new_g, new_b);
src_r = new_r;
src_g = new_g;
src_b = new_b;
src_a = KMIN(src_a, dst_a);
}
break;
case VALUE_MODE: {
uchar new_r = dst_r;
uchar new_g = dst_g;
uchar new_b = dst_b;
RGBTOHSV(src_r, src_g, src_b);
RGBTOHSV(new_r, new_g, new_b);
new_b = src_b;
HSVTORGB(new_r, new_g, new_b);
src_r = new_r;
src_g = new_g;
src_b = new_b;
src_a = KMIN(src_a, dst_a);
}
break;
case COLOR_MODE: {
uchar new_r = dst_r;
uchar new_g = dst_g;
uchar new_b = dst_b;
RGBTOHLS(src_r, src_g, src_b);
RGBTOHLS(new_r, new_g, new_b);
new_r = src_r;
new_b = src_b;
HLSTORGB(new_r, new_g, new_b);
src_r = new_r;
src_g = new_g;
src_b = new_b;
src_a = KMIN(src_a, dst_a);
}
break;
}
src_a = INT_MULT(src_a, layer.opacity);
// Apply the mask (if any)
if (layer.apply_mask == 1 && layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
uchar new_r, new_g, new_b, new_a;
new_a = dst_a + INT_MULT(OPAQUE_OPACITY - dst_a, src_a);
float src_ratio = (float)src_a / new_a;
float dst_ratio = 1.0 - src_ratio;
new_r = (uchar)(src_ratio * src_r + dst_ratio * dst_r + EPSILON);
new_g = (uchar)(src_ratio * src_g + dst_ratio * dst_g + EPSILON);
new_b = (uchar)(src_ratio * src_b + dst_ratio * dst_b + EPSILON);
if (!layer_modes[layer.mode].affect_alpha)
new_a = dst_a;
image.setPixel(m, n, qRgba(new_r, new_g, new_b, new_a));
}
void XCFImageFormat::mergeGrayToGray(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
int src = layer.image_tiles[j][i].pixelIndex(k, l);
image.setPixel(m, n, src);
}
void XCFImageFormat::mergeGrayAToGray(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
int src = qGray(layer.image_tiles[j][i].pixel(k, l));
int dst = image.pixelIndex(m, n);
uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
switch (layer.mode) {
case MULTIPLY_MODE: {
src = INT_MULT( src, dst );
}
break;
case DIVIDE_MODE: {
src = KMIN((dst * 256) / (1 + src), 255);
}
break;
case SCREEN_MODE: {
src = 255 - INT_MULT(255 - dst, 255 - src);
}
break;
case OVERLAY_MODE: {
src = INT_MULT(dst, dst + INT_MULT(2 * src, 255 - dst));
}
break;
case DIFFERENCE_MODE: {
src = dst > src ? dst - src : src - dst;
}
break;
case ADDITION_MODE: {
src = add_lut(dst,src);
}
break;
case SUBTRACT_MODE: {
src = dst > src ? dst - src : 0;
}
break;
case DARKEN_ONLY_MODE: {
src = dst < src ? dst : src;
}
break;
case LIGHTEN_ONLY_MODE: {
src = dst < src ? src : dst;
}
break;
}
src_a = INT_MULT(src_a, layer.opacity);
// Apply the mask (if any)
if (layer.apply_mask == 1 && layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
uchar new_a = OPAQUE_OPACITY;
float src_ratio = (float)src_a / new_a;
float dst_ratio = 1.0 - src_ratio;
uchar new_g = (uchar)(src_ratio * src + dst_ratio * dst + EPSILON);
image.setPixel(m, n, new_g);
}
void XCFImageFormat::mergeGrayToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
QRgb src = layer.image_tiles[j][i].pixel(k, l);
uchar src_a = layer.opacity;
image.setPixel(m, n, qRgba(src, src_a));
}
void XCFImageFormat::mergeGrayAToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
int src = qGray(layer.image_tiles[j][i].pixel(k, l));
int dst = qGray(image.pixel(m, n));
uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
uchar dst_a = qAlpha(image.pixel(m, n));
switch (layer.mode) {
case MULTIPLY_MODE: {
src = INT_MULT(src, dst);
src_a = KMIN(src_a, dst_a);
}
break;
case DIVIDE_MODE: {
src = KMIN((dst * 256) / (1 + src), 255);
src_a = KMIN(src_a, dst_a);
}
break;
case SCREEN_MODE: {
src = 255 - INT_MULT(255 - dst, 255 - src);
src_a = KMIN(src_a, dst_a);
}
break;
case OVERLAY_MODE: {
src = INT_MULT( dst, dst + INT_MULT(2 * src, 255 - dst));
src_a = KMIN(src_a, dst_a);
}
break;
case DIFFERENCE_MODE: {
src = dst > src ? dst - src : src - dst;
src_a = KMIN(src_a, dst_a);
}
break;
case ADDITION_MODE: {
src = add_lut(dst,src);
src_a = KMIN(src_a, dst_a);
}
break;
case SUBTRACT_MODE: {
src = dst > src ? dst - src : 0;
src_a = KMIN(src_a, dst_a);
}
break;
case DARKEN_ONLY_MODE: {
src = dst < src ? dst : src;
src_a = KMIN(src_a, dst_a);
}
break;
case LIGHTEN_ONLY_MODE: {
src = dst < src ? src : dst;
src_a = KMIN(src_a, dst_a);
}
break;
}
src_a = INT_MULT(src_a, layer.opacity);
// Apply the mask (if any)
if (layer.apply_mask == 1 && layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
uchar new_a = dst_a + INT_MULT(OPAQUE_OPACITY - dst_a, src_a);
float src_ratio = (float)src_a / new_a;
float dst_ratio = 1.0 - src_ratio;
uchar new_g = (uchar)(src_ratio * src + dst_ratio * dst + EPSILON);
if (!layer_modes[layer.mode].affect_alpha)
new_a = dst_a;
image.setPixel(m, n, qRgba(new_g, new_g, new_g, new_a));
}
void XCFImageFormat::mergeIndexedToIndexed(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
int src = layer.image_tiles[j][i].pixelIndex(k, l);
image.setPixel(m, n, src);
}
void XCFImageFormat::mergeIndexedAToIndexed(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
uchar src = layer.image_tiles[j][i].pixelIndex(k, l);
uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
src_a = INT_MULT( src_a, layer.opacity );
if ( layer.apply_mask == 1 &&
layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
if (src_a > 127) {
src++;
image.setPixel(m, n, src);
}
}
void XCFImageFormat::mergeIndexedAToRGB(Layer& layer, uint i, uint j, int k, int l,
QImage& image, int m, int n)
{
QRgb src = layer.image_tiles[j][i].pixel(k, l);
uchar src_a = layer.alpha_tiles[j][i].pixelIndex(k, l);
src_a = INT_MULT(src_a, layer.opacity);
// Apply the mask (if any)
if (layer.apply_mask == 1 && layer.mask_tiles.size() > j &&
layer.mask_tiles[j].size() > i)
src_a = INT_MULT(src_a, layer.mask_tiles[j][i].pixelIndex(k, l));
// This is what appears in the GIMP window
if (src_a <= 127)
src_a = 0;
else
src_a = OPAQUE_OPACITY;
image.setPixel(m, n, qRgba(src, src_a));
}
void XCFImageFormat::dissolveRGBPixels ( QImage& image, int x, int y )
{
// The apparently spurious rand() calls are to wind the random
// numbers up to the same point for each tile.
for (int l = 0; l < image.height(); l++) {
srand(random_table[( l + y ) % RANDOM_TABLE_SIZE]);
for (int k = 0; k < x; k++)
rand();
for (int k = 0; k < image.width(); k++) {
int rand_val = rand() & 0xff;
QRgb pixel = image.pixel(k, l);
if (rand_val > qAlpha(pixel)) {
image.setPixel(k, l, qRgba(pixel, 0));
}
}
}
}
void XCFImageFormat::dissolveAlphaPixels ( QImage& image, int x, int y )
{
// The apparently spurious rand() calls are to wind the random
// numbers up to the same point for each tile.
for (int l = 0; l < image.height(); l++) {
srand( random_table[(l + y) % RANDOM_TABLE_SIZE]);
for (int k = 0; k < x; k++)
rand();
for (int k = 0; k < image.width(); k++) {
int rand_val = rand() & 0xff;
uchar alpha = image.pixelIndex(k, l);
if (rand_val > alpha) {
image.setPixel(k, l, 0);
}
}
}
}

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