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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.geom.Point2D;
import java.awt.image.ColorModel;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.io.EOFException;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import javax.imageio.stream.ImageInputStream;
import javax.imageio.stream.MemoryCacheImageInputStream;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSStream;
import org.apache.pdfbox.pdmodel.common.PDRange;
import org.apache.pdfbox.util.Matrix;
/**
* This class is extended in Type6ShadingContext and Type7ShadingContext. This
* was done as part of GSoC2014, Tilman Hausherr is the mentor.
*
* @author Shaola Ren
*/
abstract class PatchMeshesShadingContext extends TriangleBasedShadingContext implements PaintContext
{
private static final Log LOG = LogFactory.getLog(PatchMeshesShadingContext.class);
protected float[] background; // background values.
protected int rgbBackground;
protected final PDShadingResources patchMeshesShadingType;
// the following fields are not intialized in this abstract class
protected ArrayList patchList; // patch list
protected int bitsPerFlag; // bits per flag
protected HashMap pixelTable;
/**
* 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
* @throws IOException if something went wrong
*/
protected PatchMeshesShadingContext(PDShadingResources shading, ColorModel colorModel, AffineTransform xform,
Matrix ctm, int pageHeight, Rectangle dBounds) throws IOException
{
super(shading, colorModel, xform, ctm, pageHeight, dBounds);
patchMeshesShadingType = shading;
bitsPerFlag = ((PDShadingType6) shading).getBitsPerFlag();
patchList = new ArrayList();
COSArray bg = shading.getBackground();
if (bg != null)
{
background = bg.toFloatArray();
rgbBackground = convertToRGB(background);
}
}
/**
* Create a patch list from a data stream, the returned list contains all
* the patches contained in the data stream.
*
* @param xform transformation for user to device space
* @param ctm current transformation matrix
* @param cosDictionary dictionary object to give the image information
* @param rangeX range for coordinate x
* @param rangeY range for coordinate y
* @param colRange range for color
* @param numP number of control points, 12 for type 6 shading and 16 for
* type 7 shading
* @return the obtained patch list
* @throws IOException when something went wrong
*/
protected ArrayList getPatchList(AffineTransform xform, Matrix ctm, COSDictionary cosDictionary,
PDRange rangeX, PDRange rangeY, PDRange[] colRange, int numP) throws IOException
{
ArrayList list = new ArrayList();
long maxSrcCoord = (long) Math.pow(2, bitsPerCoordinate) - 1;
long maxSrcColor = (long) Math.pow(2, bitsPerColorComponent) - 1;
COSStream cosStream = (COSStream) cosDictionary;
ImageInputStream mciis = new MemoryCacheImageInputStream(cosStream.getUnfilteredStream());
Point2D[] implicitEdge = new Point2D[4];
float[][] implicitCornerColor = new float[2][numberOfColorComponents];
byte flag = (byte) 0;
try
{
flag = (byte) (mciis.readBits(bitsPerFlag) & 3);
}
catch (EOFException ex)
{
LOG.error(ex);
}
while (true)
{
try
{
boolean isFree = (flag == 0);
Patch current = readPatch(mciis, isFree, implicitEdge, implicitCornerColor,
maxSrcCoord, maxSrcColor, rangeX, rangeY, colRange, ctm, xform, numP);
if (current == null)
{
break;
}
list.add((Patch) current);
flag = (byte) (mciis.readBits(bitsPerFlag) & 3);
switch (flag)
{
case 0:
break;
case 1:
implicitEdge = current.getFlag1Edge();
implicitCornerColor = current.getFlag1Color();
break;
case 2:
implicitEdge = current.getFlag2Edge();
implicitCornerColor = current.getFlag2Color();
break;
case 3:
implicitEdge = current.getFlag3Edge();
implicitCornerColor = current.getFlag3Color();
break;
default:
LOG.warn("bad flag: " + flag);
break;
}
}
catch (EOFException ex)
{
break;
}
}
mciis.close();
return list;
}
/**
* Read a single patch from a data stream, a patch contains information of
* its coordinates and color parameters.
*
* @param input the image source data stream
* @param isFree whether this is a free patch
* @param implicitEdge implicit edge when a patch is not free, otherwise
* it's not used
* @param implicitCornerColor implicit colors when a patch is not free,
* otherwise it's not used
* @param maxSrcCoord the maximum coordinate value calculated from source
* data
* @param maxSrcColor the maximum color value calculated from source data
* @param rangeX range for coordinate x
* @param rangeY range for coordinate y
* @param colRange range for color
* @param ctm current transformation matrix
* @param xform transformation for user to device space
* @param numP number of control points, 12 for type 6 shading and 16 for
* type 7 shading
* @return a single patch
* @throws IOException when something went wrong
*/
protected Patch readPatch(ImageInputStream input, boolean isFree, Point2D[] implicitEdge,
float[][] implicitCornerColor, long maxSrcCoord, long maxSrcColor,
PDRange rangeX, PDRange rangeY, PDRange[] colRange,
Matrix ctm, AffineTransform xform, int numP) throws IOException
{
float[][] color = new float[4][numberOfColorComponents];
Point2D[] points = new Point2D[numP];
int pStart = 4, cStart = 2;
if (isFree)
{
pStart = 0;
cStart = 0;
}
else
{
points[0] = implicitEdge[0];
points[1] = implicitEdge[1];
points[2] = implicitEdge[2];
points[3] = implicitEdge[3];
for (int i = 0; i < numberOfColorComponents; i++)
{
color[0][i] = implicitCornerColor[0][i];
color[1][i] = implicitCornerColor[1][i];
}
}
try
{
for (int i = pStart; i < numP; i++)
{
long x = input.readBits(bitsPerCoordinate);
long y = input.readBits(bitsPerCoordinate);
double px = interpolate(x, maxSrcCoord, rangeX.getMin(), rangeX.getMax());
double py = interpolate(y, maxSrcCoord, rangeY.getMin(), rangeY.getMax());
Point2D tmp = new Point2D.Double(px, py);
transformPoint(tmp, ctm, xform);
points[i] = tmp;
}
for (int i = cStart; i < 4; i++)
{
for (int j = 0; j < numberOfColorComponents; j++)
{
long c = input.readBits(bitsPerColorComponent);
color[i][j] = (float) interpolate(c, maxSrcColor, colRange[j].getMin(), colRange[j].getMax());
}
}
}
catch (EOFException ex)
{
LOG.debug("EOF");
return null;
}
return generatePatch(points, color);
}
/**
* Create a patch using control points and 4 corner color values, in
* Type6ShadingContext, a CoonsPatch is returned; in Type6ShadingContext, a
* TensorPatch is returned.
*
* @param points 12 or 16 control points
* @param color 4 corner colors
* @return a patch instance
*/
abstract Patch generatePatch(Point2D[] points, float[][] color);
// get a point coordinate on a line by linear interpolation
private double interpolate(double x, long maxValue, float rangeMin, float rangeMax)
{
return rangeMin + (x / maxValue) * (rangeMax - rangeMin);
}
/**
* 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
*/
protected HashMap calcPixelTable()
{
HashMap map = new HashMap();
for (Patch it : patchList)
{
super.calcPixelTable(it.listOfTriangles, map);
}
return map;
}
/**
* {@inheritDoc}
*/
public void dispose()
{
patchList = null;
outputColorModel = null;
shadingColorSpace = null;
shadingTinttransform = null;
}
/**
* {@inheritDoc}
*/
public final ColorModel getColorModel()
{
return outputColorModel;
}
/**
* {@inheritDoc}
*/
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 (!patchList.isEmpty() || background != null)
{
for (int row = 0; row < h; row++)
{
int currentY = y + row;
if (bboxRect != null)
{
if (currentY < minBBoxY || currentY > maxBBoxY)
{
continue;
}
}
for (int col = 0; col < w; col++)
{
int currentX = x + col;
if (bboxRect != null)
{
if (currentX < minBBoxX || currentX > maxBBoxX)
{
continue;
}
}
Point p = new Point(x + col, y + row);
int value;
if (pixelTable.containsKey(p))
{
value = pixelTable.get(p);
}
else
{
if (background != null)
{
value = rgbBackground;
}
else
{
continue;
}
}
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;
}
}