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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.Rectangle;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.image.ColorModel;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.io.IOException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.util.Matrix;
/**
* AWT PaintContext for function-based (Type 1) shading.
*
* @author Andreas Lehmk?hler
* @author Tilman Hausherr
*/
class Type1ShadingContext extends ShadingContext implements PaintContext
{
private static final Log LOG = LogFactory.getLog(Type1ShadingContext.class);
private PDShadingType1 type1ShadingType;
private AffineTransform rat;
private final float[] domain;
private Matrix matrix;
private float[] background;
/**
* Constructor creates an instance to be used for fill operations.
*
* @param shading the shading type to be used
* @param colorModel the color model to be used
* @param xform transformation for user to device space
* @param ctm current transformation matrix
* @param pageHeight height of the current page
* @param dBounds device bounds
*/
public Type1ShadingContext(PDShadingType1 shading, ColorModel colorModel, AffineTransform xform,
Matrix ctm, int pageHeight, Rectangle dBounds) throws IOException
{
super(shading, colorModel, xform, ctm, pageHeight, dBounds);
this.type1ShadingType = shading;
// PDFBOX-1966 flip the AffineTransform in 1.8 branch
//TODO find out why AffineTransform passed in 1.8 branch is flipped
xform.scale(1, -1);
xform.translate(0, -pageHeight);
// spec p.308
// (Optional) An array of four numbers [ xmin xmax ymin ymax ]
// specifying the rectangular domain of coordinates over which the
// color function(s) are defined. Default value: [ 0.0 1.0 0.0 1.0 ].
if (shading.getDomain() != null)
{
domain = shading.getDomain().toFloatArray();
}
else
{
domain = new float[]
{
0, 1, 0, 1
};
}
matrix = shading.getMatrix();
if (matrix == null)
{
matrix = new Matrix();
}
try
{
// get inverse transform to be independent of
// shading matrix and current user / device space
// when handling actual pixels in getRaster()
rat = matrix.createAffineTransform().createInverse();
rat.concatenate(ctm.createAffineTransform().createInverse());
rat.concatenate(xform.createInverse());
}
catch (NoninvertibleTransformException ex)
{
LOG.error(ex, ex);
}
// get background values if available
COSArray bg = shading.getBackground();
if (bg != null)
{
background = bg.toFloatArray();
}
}
/**
* {@inheritDoc}
*/
public void dispose()
{
outputColorModel = null;
shadingColorSpace = null;
shadingTinttransform = null;
type1ShadingType = null;
}
/**
* {@inheritDoc}
*/
public ColorModel getColorModel()
{
return outputColorModel;
}
/**
* {@inheritDoc}
*/
public Raster getRaster(int x, int y, int w, int h)
{
WritableRaster raster = getColorModel().createCompatibleWritableRaster(w, h);
int[] data = new int[w * h * 4];
for (int j = 0; j < h; j++)
{
int currentY = y + j;
if (bboxRect != null)
{
if (currentY < minBBoxY || currentY > maxBBoxY)
{
continue;
}
}
for (int i = 0; i < w; i++)
{
int currentX = x + i;
if (bboxRect != null)
{
if (currentX < minBBoxX || currentX > maxBBoxX)
{
continue;
}
}
int index = (j * w + i) * 4;
boolean useBackground = false;
float[] values = new float[]
{
x + i, y + j
};
rat.transform(values, 0, values, 0, 1);
if (values[0] < domain[0] || values[0] > domain[1] || values[1] < domain[2] || values[1] > domain[3])
{
if (background != null)
{
useBackground = true;
}
else
{
continue;
}
}
try
{
if (useBackground)
{
values = background;
}
else
{
values = type1ShadingType.evalFunction(values);
}
// convert color values from shading colorspace to RGB
if (shadingColorSpace != null)
{
if (shadingTinttransform != null)
{
values = shadingTinttransform.eval(values);
}
values = shadingColorSpace.toRGB(values);
}
}
catch (IOException exception)
{
LOG.error("error while processing a function", exception);
}
data[index] = (int) (values[0] * 255);
data[index + 1] = (int) (values[1] * 255);
data[index + 2] = (int) (values[2] * 255);
data[index + 3] = 255;
}
}
raster.setPixels(0, 0, w, h, data);
return raster;
}
public float[] getDomain()
{
return domain;
}
}