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sdk-common library used by other Android tools libraries.
/*
* Copyright (C) 2015 The Android Open Source Project
*
* 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 com.android.ide.common.vectordrawable;
import java.awt.geom.Path2D;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* Given an array of VdPath.Node, generate a Path2D object.
* In another word, this is the engine which converts the pathData into
* a Path2D object, which is able to draw on Swing components.
* The logic and math here are the same as PathParser.java in framework.
*/
class VdNodeRender {
private static Logger logger = Logger.getLogger(VdNodeRender.class
.getSimpleName());
public static void creatPath(VdPath.Node[] node, Path2D path) {
float[] current = new float[6];
char lastCmd = ' ';
for (int i = 0; i < node.length; i++) {
addCommand(path, current, node[i].getType(), lastCmd,node[i].getmParams());
lastCmd = node[i].getType();
}
}
private static void addCommand(Path2D path, float[] current, char cmd,
char lastCmd, float[] val) {
int incr = 2;
float cx = current[0];
float cy = current[1];
float cpx = current[2];
float cpy = current[3];
float loopX = current[4];
float loopY = current[5];
switch (cmd) {
case 'z':
case 'Z':
path.closePath();
cx = loopX;
cy = loopY;
case 'm':
case 'M':
case 'l':
case 'L':
case 't':
case 'T':
incr = 2;
break;
case 'h':
case 'H':
case 'v':
case 'V':
incr = 1;
break;
case 'c':
case 'C':
incr = 6;
break;
case 's':
case 'S':
case 'q':
case 'Q':
incr = 4;
break;
case 'a':
case 'A':
incr = 7;
}
for (int k = 0; k < val.length; k += incr) {
boolean reflectCtrl = false;
float tempReflectedX, tempReflectedY;
switch (cmd) {
case 'm':
cx += val[k + 0];
cy += val[k + 1];
if (k > 0) {
// According to the spec, if a moveto is followed by multiple
// pairs of coordinates, the subsequent pairs are treated as
// implicit lineto commands.
path.lineTo(cx, cy);
} else {
path.moveTo(cx, cy);
loopX = cx;
loopY = cy;
}
break;
case 'M':
cx = val[k + 0];
cy = val[k + 1];
if (k > 0) {
// According to the spec, if a moveto is followed by multiple
// pairs of coordinates, the subsequent pairs are treated as
// implicit lineto commands.
path.lineTo(cx, cy);
} else {
path.moveTo(cx, cy);
loopX = cx;
loopY = cy;
}
break;
case 'l':
cx += val[k + 0];
cy += val[k + 1];
path.lineTo(cx, cy);
break;
case 'L':
cx = val[k + 0];
cy = val[k + 1];
path.lineTo(cx, cy);
break;
case 'z':
case 'Z':
path.closePath();
cx = loopX;
cy = loopY;
break;
case 'h':
cx += val[k + 0];
path.lineTo(cx, cy);
break;
case 'H':
path.lineTo(val[k + 0], cy);
cx = val[k + 0];
break;
case 'v':
cy += val[k + 0];
path.lineTo(cx, cy);
break;
case 'V':
path.lineTo(cx, val[k + 0]);
cy = val[k + 0];
break;
case 'c':
path.curveTo(cx + val[k + 0], cy + val[k + 1], cx + val[k + 2],
cy + val[k + 3], cx + val[k + 4], cy + val[k + 5]);
cpx = cx + val[k + 2];
cpy = cy + val[k + 3];
cx += val[k + 4];
cy += val[k + 5];
break;
case 'C':
path.curveTo(val[k + 0], val[k + 1], val[k + 2], val[k + 3],
val[k + 4], val[k + 5]);
cx = val[k + 4];
cy = val[k + 5];
cpx = val[k + 2];
cpy = val[k + 3];
break;
case 's':
reflectCtrl = (lastCmd == 'c' || lastCmd == 's' || lastCmd == 'C' || lastCmd == 'S');
path.curveTo(reflectCtrl ? 2 * cx - cpx : cx, reflectCtrl ? 2
* cy - cpy : cy, cx + val[k + 0], cy + val[k + 1], cx
+ val[k + 2], cy + val[k + 3]);
cpx = cx + val[k + 0];
cpy = cy + val[k + 1];
cx += val[k + 2];
cy += val[k + 3];
break;
case 'S':
reflectCtrl = (lastCmd == 'c' || lastCmd == 's' || lastCmd == 'C' || lastCmd == 'S');
path.curveTo(reflectCtrl ? 2 * cx - cpx : cx, reflectCtrl ? 2
* cy - cpy : cy, val[k + 0], val[k + 1], val[k + 2],
val[k + 3]);
cpx = (val[k + 0]);
cpy = (val[k + 1]);
cx = val[k + 2];
cy = val[k + 3];
break;
case 'q':
path.quadTo(cx + val[k + 0], cy + val[k + 1], cx + val[k + 2],
cy + val[k + 3]);
cpx = cx + val[k + 0];
cpy = cy + val[k + 1];
// Note that we have to update cpx first, since cx will be updated here.
cx += val[k + 2];
cy += val[k + 3];
break;
case 'Q':
path.quadTo(val[k + 0], val[k + 1], val[k + 2], val[k + 3]);
cx = val[k + 2];
cy = val[k + 3];
cpx = val[k + 0];
cpy = val[k + 1];
break;
case 't':
reflectCtrl = (lastCmd == 'q' || lastCmd == 't' || lastCmd == 'Q' || lastCmd == 'T');
tempReflectedX = reflectCtrl ? 2 * cx - cpx : cx;
tempReflectedY = reflectCtrl ? 2 * cy - cpy : cy;
path.quadTo(tempReflectedX, tempReflectedY, cx + val[k + 0], cy + val[k + 1]);
cpx = tempReflectedX;
cpy = tempReflectedY;
cx += val[k + 0];
cy += val[k + 1];
break;
case 'T':
reflectCtrl = (lastCmd == 'q' || lastCmd == 't' || lastCmd == 'Q' || lastCmd == 'T');
tempReflectedX = reflectCtrl ? 2 * cx - cpx : cx;
tempReflectedY = reflectCtrl ? 2 * cy - cpy : cy;
path.quadTo(tempReflectedX, tempReflectedY, val[k + 0], val[k + 1]);
cx = val[k + 0];
cy = val[k + 1];
cpx = tempReflectedX;
cpy = tempReflectedY;
break;
case 'a':
// (rx ry x-axis-rotation large-arc-flag sweep-flag x y)
drawArc(path, cx, cy, val[k + 5] + cx, val[k + 6] + cy,
val[k + 0], val[k + 1], val[k + 2], val[k + 3] != 0,
val[k + 4] != 0);
cx += val[k + 5];
cy += val[k + 6];
cpx = cx;
cpy = cy;
break;
case 'A':
drawArc(path, cx, cy, val[k + 5], val[k + 6], val[k + 0],
val[k + 1], val[k + 2], val[k + 3] != 0,
val[k + 4] != 0);
cx = val[k + 5];
cy = val[k + 6];
cpx = cx;
cpy = cy;
break;
}
lastCmd = cmd;
}
current[0] = cx;
current[1] = cy;
current[2] = cpx;
current[3] = cpy;
current[4] = loopX;
current[5] = loopY;
}
private static void drawArc(Path2D p, float x0, float y0, float x1,
float y1, float a, float b, float theta, boolean isMoreThanHalf,
boolean isPositiveArc) {
logger.log(Level.FINE, "(" + x0 + "," + y0 + ")-(" + x1 + "," + y1
+ ") {" + a + " " + b + "}");
/* Convert rotation angle from degrees to radians */
double thetaD = theta * Math.PI / 180.0f;
/* Pre-compute rotation matrix entries */
double cosTheta = Math.cos(thetaD);
double sinTheta = Math.sin(thetaD);
/* Transform (x0, y0) and (x1, y1) into unit space */
/* using (inverse) rotation, followed by (inverse) scale */
double x0p = (x0 * cosTheta + y0 * sinTheta) / a;
double y0p = (-x0 * sinTheta + y0 * cosTheta) / b;
double x1p = (x1 * cosTheta + y1 * sinTheta) / a;
double y1p = (-x1 * sinTheta + y1 * cosTheta) / b;
logger.log(Level.FINE, "unit space (" + x0p + "," + y0p + ")-(" + x1p
+ "," + y1p + ")");
/* Compute differences and averages */
double dx = x0p - x1p;
double dy = y0p - y1p;
double xm = (x0p + x1p) / 2;
double ym = (y0p + y1p) / 2;
/* Solve for intersecting unit circles */
double dsq = dx * dx + dy * dy;
if (dsq == 0.0) {
logger.log(Level.FINE, " Points are coincident");
return; /* Points are coincident */
}
double disc = 1.0 / dsq - 1.0 / 4.0;
if (disc < 0.0) {
logger.log(Level.FINE, "Points are too far apart " + dsq);
float adjust = (float) (Math.sqrt(dsq) / 1.99999);
drawArc(p, x0, y0, x1, y1, a * adjust, b * adjust, theta,
isMoreThanHalf, isPositiveArc);
return; /* Points are too far apart */
}
double s = Math.sqrt(disc);
double sdx = s * dx;
double sdy = s * dy;
double cx;
double cy;
if (isMoreThanHalf == isPositiveArc) {
cx = xm - sdy;
cy = ym + sdx;
} else {
cx = xm + sdy;
cy = ym - sdx;
}
double eta0 = Math.atan2((y0p - cy), (x0p - cx));
logger.log(Level.FINE, "eta0 = Math.atan2( " + (y0p - cy) + " , "
+ (x0p - cx) + ") = " + Math.toDegrees(eta0));
double eta1 = Math.atan2((y1p - cy), (x1p - cx));
logger.log(Level.FINE, "eta1 = Math.atan2( " + (y1p - cy) + " , "
+ (x1p - cx) + ") = " + Math.toDegrees(eta1));
double sweep = (eta1 - eta0);
if (isPositiveArc != (sweep >= 0)) {
if (sweep > 0) {
sweep -= 2 * Math.PI;
} else {
sweep += 2 * Math.PI;
}
}
cx *= a;
cy *= b;
double tcx = cx;
cx = cx * cosTheta - cy * sinTheta;
cy = tcx * sinTheta + cy * cosTheta;
logger.log(
Level.FINE,
"cx, cy, a, b, x0, y0, thetaD, eta0, sweep = " + cx + " , "
+ cy + " , " + a + " , " + b + " , " + x0 + " , " + y0
+ " , " + Math.toDegrees(thetaD) + " , "
+ Math.toDegrees(eta0) + " , " + Math.toDegrees(sweep));
arcToBezier(p, cx, cy, a, b, x0, y0, thetaD, eta0, sweep);
}
/**
* Converts an arc to cubic Bezier segments and records them in p.
*
* @param p The target for the cubic Bezier segments
* @param cx The x coordinate center of the ellipse
* @param cy The y coordinate center of the ellipse
* @param a The radius of the ellipse in the horizontal direction
* @param b The radius of the ellipse in the vertical direction
* @param e1x E(eta1) x coordinate of the starting point of the arc
* @param e1y E(eta2) y coordinate of the starting point of the arc
* @param theta The angle that the ellipse bounding rectangle makes with the horizontal plane
* @param start The start angle of the arc on the ellipse
* @param sweep The angle (positive or negative) of the sweep of the arc on the ellipse
*/
private static void arcToBezier(Path2D p, double cx, double cy, double a,
double b, double e1x, double e1y, double theta, double start,
double sweep) {
// Taken from equations at:
// http://spaceroots.org/documents/ellipse/node8.html
// and http://www.spaceroots.org/documents/ellipse/node22.html
// Maximum of 45 degrees per cubic Bezier segment
int numSegments = (int) Math.ceil(Math.abs(sweep * 4 / Math.PI));
double eta1 = start;
double cosTheta = Math.cos(theta);
double sinTheta = Math.sin(theta);
double cosEta1 = Math.cos(eta1);
double sinEta1 = Math.sin(eta1);
double ep1x = (-a * cosTheta * sinEta1) - (b * sinTheta * cosEta1);
double ep1y = (-a * sinTheta * sinEta1) + (b * cosTheta * cosEta1);
double anglePerSegment = sweep / numSegments;
for (int i = 0; i < numSegments; i++) {
double eta2 = eta1 + anglePerSegment;
double sinEta2 = Math.sin(eta2);
double cosEta2 = Math.cos(eta2);
double e2x = cx + (a * cosTheta * cosEta2)
- (b * sinTheta * sinEta2);
double e2y = cy + (a * sinTheta * cosEta2)
+ (b * cosTheta * sinEta2);
double ep2x = -a * cosTheta * sinEta2 - b * sinTheta * cosEta2;
double ep2y = -a * sinTheta * sinEta2 + b * cosTheta * cosEta2;
double tanDiff2 = Math.tan((eta2 - eta1) / 2);
double alpha = Math.sin(eta2 - eta1)
* (Math.sqrt(4 + (3 * tanDiff2 * tanDiff2)) - 1) / 3;
double q1x = e1x + alpha * ep1x;
double q1y = e1y + alpha * ep1y;
double q2x = e2x - alpha * ep2x;
double q2y = e2y - alpha * ep2y;
p.curveTo((float) q1x, (float) q1y, (float) q2x, (float) q2y,
(float) e2x, (float) e2y);
eta1 = eta2;
e1x = e2x;
e1y = e2y;
ep1x = ep2x;
ep1y = ep2y;
}
}
}
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