Java tutorial
/* * 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<Point, Integer> 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<Point, Integer> calcPixelTable(Rectangle deviceBounds) throws IOException; /** * Get the points from the triangles, calculate their color and add point-color mappings. */ protected void calcPixelTable(List<ShadedTriangle> triangleList, Map<Point, Integer> 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; } }