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The Apache PDFBox library is an open source Java tool for working with PDF documents.
/*
* Copyright 2014 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.pdfbox.pdmodel.graphics.shading;
import java.awt.PaintContext;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.geom.AffineTransform;
import java.awt.image.ColorModel;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.io.IOException;
import java.util.List;
import java.util.Map;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.util.Matrix;
/**
* Intermediate class extended by the shading types 4,5,6 and 7 that contains the common methods
* used by these classes.
*
* @author Shaola Ren
* @author Tilman Hausherr
*/
abstract class TriangleBasedShadingContext extends ShadingContext implements PaintContext
{
private static final Log LOG = LogFactory.getLog(TriangleBasedShadingContext.class);
protected int bitsPerCoordinate;
protected int bitsPerColorComponent;
protected int numberOfColorComponents;
private final boolean hasFunction;
// map of pixels within triangles to their RGB color
private Map pixelTable;
/**
* Constructor.
*
* @param shading the shading type to be used
* @param cm the color model to be used
* @param xform transformation for user to device space
* @param matrix the pattern matrix concatenated with that of the parent content stream
* @throws IOException if there is an error getting the color space or doing background color conversion.
*/
TriangleBasedShadingContext(PDShading shading, ColorModel cm, AffineTransform xform,
Matrix matrix) throws IOException
{
super(shading, cm, xform, matrix);
PDTriangleBasedShadingType triangleBasedShadingType = (PDTriangleBasedShadingType) shading;
hasFunction = shading.getFunction() != null;
bitsPerCoordinate = triangleBasedShadingType.getBitsPerCoordinate();
LOG.debug("bitsPerCoordinate: " + (Math.pow(2, bitsPerCoordinate) - 1));
bitsPerColorComponent = triangleBasedShadingType.getBitsPerComponent();
LOG.debug("bitsPerColorComponent: " + bitsPerColorComponent);
numberOfColorComponents = hasFunction ? 1 : getShadingColorSpace().getNumberOfComponents();
LOG.debug("numberOfColorComponents: " + numberOfColorComponents);
}
/**
* Creates the pixel table.
*/
protected final void createPixelTable(Rectangle deviceBounds) throws IOException
{
pixelTable = calcPixelTable(deviceBounds);
}
/**
* Calculate every point and its color and store them in a Hash table.
*
* @return a Hash table which contains all the points' positions and colors of one image
*/
abstract Map calcPixelTable(Rectangle deviceBounds) throws IOException;
/**
* Get the points from the triangles, calculate their color and add point-color mappings.
*/
protected void calcPixelTable(List triangleList, Map map,
Rectangle deviceBounds) throws IOException
{
for (ShadedTriangle tri : triangleList)
{
int degree = tri.getDeg();
if (degree == 2)
{
Line line = tri.getLine();
for (Point p : line.linePoints)
{
map.put(p, evalFunctionAndConvertToRGB(line.calcColor(p)));
}
}
else
{
int[] boundary = tri.getBoundary();
boundary[0] = Math.max(boundary[0], deviceBounds.x);
boundary[1] = Math.min(boundary[1], deviceBounds.x + deviceBounds.width);
boundary[2] = Math.max(boundary[2], deviceBounds.y);
boundary[3] = Math.min(boundary[3], deviceBounds.y + deviceBounds.height);
for (int x = boundary[0]; x <= boundary[1]; x++)
{
for (int y = boundary[2]; y <= boundary[3]; y++)
{
Point p = new Point(x, y);
if (tri.contains(p))
{
map.put(p, evalFunctionAndConvertToRGB(tri.calcColor(p)));
}
}
}
}
}
}
/**
* Convert color to RGB color value, using function if required, then convert from the shading
* color space to an RGB value, which is encoded into an integer.
*/
private int evalFunctionAndConvertToRGB(float[] values) throws IOException
{
if (hasFunction)
{
values = getShading().evalFunction(values);
}
return convertToRGB(values);
}
/**
* Returns true if the shading has an empty data stream.
*/
abstract boolean isDataEmpty();
@Override
public final ColorModel getColorModel()
{
return super.getColorModel();
}
@Override
public void dispose()
{
super.dispose();
}
@Override
public final Raster getRaster(int x, int y, int w, int h)
{
WritableRaster raster = getColorModel().createCompatibleWritableRaster(w, h);
int[] data = new int[w * h * 4];
if (!isDataEmpty() || getBackground() != null)
{
for (int row = 0; row < h; row++)
{
int currentY = y + row;
if (bboxRect != null && (currentY < minBBoxY || currentY > maxBBoxY))
{
continue;
}
for (int col = 0; col < w; col++)
{
int currentX = x + col;
if (bboxRect != null && (currentX < minBBoxX || currentX > maxBBoxX))
{
continue;
}
Point p = new Point(currentX, currentY);
int value;
if (pixelTable.containsKey(p))
{
value = pixelTable.get(p);
}
else
{
if (getBackground() == null)
{
continue;
}
value = getRgbBackground();
}
int index = (row * w + col) * 4;
data[index] = value & 255;
value >>= 8;
data[index + 1] = value & 255;
value >>= 8;
data[index + 2] = value & 255;
data[index + 3] = 255;
}
}
}
raster.setPixels(0, 0, w, h, data);
return raster;
}
}