Showing the changes to java/pkg/java/awt/LinearGradientPaintContext.java (1 of 18352 files). Show all
Unified · Split
| @@ -0,0 +1,165 @@ | ||
| 1 | +/* | |
| 2 | + * Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved. | |
| 3 | + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 | + * | |
| 5 | + * This code is free software; you can redistribute it and/or modify it | |
| 6 | + * under the terms of the GNU General Public License version 2 only, as | |
| 7 | + * published by the Free Software Foundation. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package java.awt; | |
| 27 | + | |
| 28 | +import java.awt.MultipleGradientPaint.CycleMethod; | |
| 29 | +import java.awt.MultipleGradientPaint.ColorSpaceType; | |
| 30 | +import java.awt.geom.AffineTransform; | |
| 31 | +import java.awt.geom.Point2D; | |
| 32 | +import java.awt.geom.Rectangle2D; | |
| 33 | +import java.awt.image.ColorModel; | |
| 34 | + | |
| 35 | +/** | |
| 36 | + * Provides the actual implementation for the LinearGradientPaint. | |
| 37 | + * This is where the pixel processing is done. | |
| 38 | + * | |
| 39 | + * @see java.awt.LinearGradientPaint | |
| 40 | + * @see java.awt.PaintContext | |
| 41 | + * @see java.awt.Paint | |
| 42 | + * @author Nicholas Talian, Vincent Hardy, Jim Graham, Jerry Evans | |
| 43 | + */ | |
| 44 | +final class LinearGradientPaintContext extends MultipleGradientPaintContext { | |
| 45 | + | |
| 46 | + /** | |
| 47 | + * The following invariants are used to process the gradient value from | |
| 48 | + * a device space coordinate, (X, Y): | |
| 49 | + * g(X, Y) = dgdX*X + dgdY*Y + gc | |
| 50 | + */ | |
| 51 | + private float dgdX, dgdY, gc; | |
| 52 | + | |
| 53 | + /** | |
| 54 | + * Constructor for LinearGradientPaintContext. | |
| 55 | + * | |
| 56 | + * @param paint the {@code LinearGradientPaint} from which this context | |
| 57 | + * is created | |
| 58 | + * @param cm {@code ColorModel} that receives | |
| 59 | + * the <code>Paint</code> data. This is used only as a hint. | |
| 60 | + * @param deviceBounds the device space bounding box of the | |
| 61 | + * graphics primitive being rendered | |
| 62 | + * @param userBounds the user space bounding box of the | |
| 63 | + * graphics primitive being rendered | |
| 64 | + * @param t the {@code AffineTransform} from user | |
| 65 | + * space into device space (gradientTransform should be | |
| 66 | + * concatenated with this) | |
| 67 | + * @param hints the hints that the context object uses to choose | |
| 68 | + * between rendering alternatives | |
| 69 | + * @param dStart gradient start point, in user space | |
| 70 | + * @param dEnd gradient end point, in user space | |
| 71 | + * @param fractions the fractions specifying the gradient distribution | |
| 72 | + * @param colors the gradient colors | |
| 73 | + * @param cycleMethod either NO_CYCLE, REFLECT, or REPEAT | |
| 74 | + * @param colorSpace which colorspace to use for interpolation, | |
| 75 | + * either SRGB or LINEAR_RGB | |
| 76 | + */ | |
| 77 | + LinearGradientPaintContext(LinearGradientPaint paint, | |
| 78 | + ColorModel cm, | |
| 79 | + Rectangle deviceBounds, | |
| 80 | + Rectangle2D userBounds, | |
| 81 | + AffineTransform t, | |
| 82 | + RenderingHints hints, | |
| 83 | + Point2D start, | |
| 84 | + Point2D end, | |
| 85 | + float[] fractions, | |
| 86 | + Color[] colors, | |
| 87 | + CycleMethod cycleMethod, | |
| 88 | + ColorSpaceType colorSpace) | |
| 89 | + { | |
| 90 | + super(paint, cm, deviceBounds, userBounds, t, hints, fractions, | |
| 91 | + colors, cycleMethod, colorSpace); | |
| 92 | + | |
| 93 | + // A given point in the raster should take on the same color as its | |
| 94 | + // projection onto the gradient vector. | |
| 95 | + // Thus, we want the projection of the current position vector | |
| 96 | + // onto the gradient vector, then normalized with respect to the | |
| 97 | + // length of the gradient vector, giving a value which can be mapped | |
| 98 | + // into the range 0-1. | |
| 99 | + // projection = | |
| 100 | + // currentVector dot gradientVector / length(gradientVector) | |
| 101 | + // normalized = projection / length(gradientVector) | |
| 102 | + | |
| 103 | + float startx = (float)start.getX(); | |
| 104 | + float starty = (float)start.getY(); | |
| 105 | + float endx = (float)end.getX(); | |
| 106 | + float endy = (float)end.getY(); | |
| 107 | + | |
| 108 | + float dx = endx - startx; // change in x from start to end | |
| 109 | + float dy = endy - starty; // change in y from start to end | |
| 110 | + float dSq = dx*dx + dy*dy; // total distance squared | |
| 111 | + | |
| 112 | + // avoid repeated calculations by doing these divides once | |
| 113 | + float constX = dx/dSq; | |
| 114 | + float constY = dy/dSq; | |
| 115 | + | |
| 116 | + // incremental change along gradient for +x | |
| 117 | + dgdX = a00*constX + a10*constY; | |
| 118 | + // incremental change along gradient for +y | |
| 119 | + dgdY = a01*constX + a11*constY; | |
| 120 | + | |
| 121 | + // constant, incorporates the translation components from the matrix | |
| 122 | + gc = (a02-startx)*constX + (a12-starty)*constY; | |
| 123 | + } | |
| 124 | + | |
| 125 | + /** | |
| 126 | + * Return a Raster containing the colors generated for the graphics | |
| 127 | + * operation. This is where the area is filled with colors distributed | |
| 128 | + * linearly. | |
| 129 | + * | |
| 130 | + * @param x,y,w,h the area in device space for which colors are | |
| 131 | + * generated. | |
| 132 | + */ | |
| 133 | + protected void fillRaster(int[] pixels, int off, int adjust, | |
| 134 | + int x, int y, int w, int h) | |
| 135 | + { | |
| 136 | + // current value for row gradients | |
| 137 | + float g = 0; | |
| 138 | + | |
| 139 | + // used to end iteration on rows | |
| 140 | + int rowLimit = off + w; | |
| 141 | + | |
| 142 | + // constant which can be pulled out of the inner loop | |
| 143 | + float initConst = (dgdX*x) + gc; | |
| 144 | + | |
| 145 | + for (int i = 0; i < h; i++) { // for every row | |
| 146 | + | |
| 147 | + // initialize current value to be start | |
| 148 | + g = initConst + dgdY*(y+i); | |
| 149 | + | |
| 150 | + while (off < rowLimit) { // for every pixel in this row | |
| 151 | + // get the color | |
| 152 | + pixels[off++] = indexIntoGradientsArrays(g); | |
| 153 | + | |
| 154 | + // incremental change in g | |
| 155 | + g += dgdX; | |
| 156 | + } | |
| 157 | + | |
| 158 | + // change in off from row to row | |
| 159 | + off += adjust; | |
| 160 | + | |
| 161 | + //rowlimit is width + offset | |
| 162 | + rowLimit = off + w; | |
| 163 | + } | |
| 164 | + } | |
| 165 | +} | |