summaryrefslogtreecommitdiffstats
path: root/core/java/android/util/PathParser.java
diff options
context:
space:
mode:
Diffstat (limited to 'core/java/android/util/PathParser.java')
-rw-r--r--core/java/android/util/PathParser.java528
1 files changed, 528 insertions, 0 deletions
diff --git a/core/java/android/util/PathParser.java b/core/java/android/util/PathParser.java
new file mode 100644
index 0000000..f90ce51
--- /dev/null
+++ b/core/java/android/util/PathParser.java
@@ -0,0 +1,528 @@
+/*
+ * Copyright (C) 2014 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 android.util;
+
+import android.graphics.Path;
+import android.util.Log;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+/**
+ * @hide
+ */
+public class PathParser {
+ static final String LOGTAG = PathParser.class.getSimpleName();
+
+ /**
+ * @param pathData The string representing a path, the same as "d" string in svg file.
+ * @return the generated Path object.
+ */
+ public static Path createPathFromPathData(String pathData) {
+ Path path = new Path();
+ PathDataNode[] nodes = createNodesFromPathData(pathData);
+ if (nodes != null) {
+ PathDataNode.nodesToPath(nodes, path);
+ return path;
+ }
+ return null;
+ }
+
+ /**
+ * @param pathData The string representing a path, the same as "d" string in svg file.
+ * @return an array of the PathDataNode.
+ */
+ public static PathDataNode[] createNodesFromPathData(String pathData) {
+ int start = 0;
+ int end = 1;
+
+ ArrayList<PathDataNode> list = new ArrayList<PathDataNode>();
+ while (end < pathData.length()) {
+ end = nextStart(pathData, end);
+ String s = pathData.substring(start, end);
+ float[] val = getFloats(s);
+ addNode(list, s.charAt(0), val);
+
+ start = end;
+ end++;
+ }
+ if ((end - start) == 1 && start < pathData.length()) {
+ addNode(list, pathData.charAt(start), new float[0]);
+ }
+ return list.toArray(new PathDataNode[list.size()]);
+ }
+
+ private static int nextStart(String s, int end) {
+ char c;
+
+ while (end < s.length()) {
+ c = s.charAt(end);
+ if (((c - 'A') * (c - 'Z') <= 0) || (((c - 'a') * (c - 'z') <= 0))) {
+ return end;
+ }
+ end++;
+ }
+ return end;
+ }
+
+ private static void addNode(ArrayList<PathDataNode> list, char cmd, float[] val) {
+ list.add(new PathDataNode(cmd, val));
+ }
+
+
+ /**
+ * Parse the floats in the string.
+ * This is an optimized version of parseFloat(s.split(",|\\s"));
+ *
+ * @param s the string containing a command and list of floats
+ * @return array of floats
+ */
+ private static float[] getFloats(String s) {
+ if (s.charAt(0) == 'z' | s.charAt(0) == 'Z') {
+ return new float[0];
+ }
+ try {
+ float[] tmp = new float[s.length()];
+ int count = 0;
+ int pos = 1, end;
+ while ((end = extract(s, pos)) >= 0) {
+ if (pos < end) {
+ tmp[count++] = Float.parseFloat(s.substring(pos, end));
+ }
+ pos = end + 1;
+ }
+ // handle the final float if there is one
+ if (pos < s.length()) {
+ tmp[count++] = Float.parseFloat(s.substring(pos, s.length()));
+ }
+ return Arrays.copyOf(tmp, count);
+ } catch (NumberFormatException e){
+ Log.e(LOGTAG,"error in parsing \""+s+"\"");
+ throw e;
+ }
+ }
+
+ /**
+ * Calculate the position of the next comma or space
+ * @param s the string to search
+ * @param start the position to start searching
+ * @return the position of the next comma or space or -1 if none found
+ */
+ private static int extract(String s, int start) {
+ int space = s.indexOf(' ', start);
+ int comma = s.indexOf(',', start);
+ if (space == -1) {
+ return comma;
+ }
+ if (comma == -1) {
+ return space;
+ }
+ return (comma > space) ? space : comma;
+ }
+
+ public static class PathDataNode {
+ private char mType;
+ private float[] mParams;
+
+ private PathDataNode(char type, float[] params) {
+ mType = type;
+ mParams = params;
+ }
+
+ private PathDataNode(PathDataNode n) {
+ mType = n.mType;
+ mParams = Arrays.copyOf(n.mParams, n.mParams.length);
+ }
+
+ public static void nodesToPath(PathDataNode[] node, Path path) {
+ float[] current = new float[4];
+ char previousCommand = 'm';
+ for (int i = 0; i < node.length; i++) {
+ addCommand(path, current, previousCommand, node[i].mType, node[i].mParams);
+ previousCommand = node[i].mType;
+ }
+ }
+
+ private static void addCommand(Path path, float[] current,
+ char previousCmd, char cmd, float[] val) {
+
+ int incr = 2;
+ float currentX = current[0];
+ float currentY = current[1];
+ float ctrlPointX = current[2];
+ float ctrlPointY = current[3];
+ float reflectiveCtrlPointX;
+ float reflectiveCtrlPointY;
+
+ switch (cmd) {
+ case 'z':
+ case 'Z':
+ path.close();
+ return;
+ 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;
+ break;
+ }
+ for (int k = 0; k < val.length; k += incr) {
+ switch (cmd) {
+ case 'm': // moveto - Start a new sub-path (relative)
+ path.rMoveTo(val[k + 0], val[k + 1]);
+ currentX += val[k + 0];
+ currentY += val[k + 1];
+ break;
+ case 'M': // moveto - Start a new sub-path
+ path.moveTo(val[k + 0], val[k + 1]);
+ currentX = val[k + 0];
+ currentY = val[k + 1];
+ break;
+ case 'l': // lineto - Draw a line from the current point (relative)
+ path.rLineTo(val[k + 0], val[k + 1]);
+ currentX += val[k + 0];
+ currentY += val[k + 1];
+ break;
+ case 'L': // lineto - Draw a line from the current point
+ path.lineTo(val[k + 0], val[k + 1]);
+ currentX = val[k + 0];
+ currentY = val[k + 1];
+ break;
+ case 'z': // closepath - Close the current subpath
+ case 'Z': // closepath - Close the current subpath
+ path.close();
+ break;
+ case 'h': // horizontal lineto - Draws a horizontal line (relative)
+ path.rLineTo(val[k + 0], 0);
+ currentX += val[k + 0];
+ break;
+ case 'H': // horizontal lineto - Draws a horizontal line
+ path.lineTo(val[k + 0], currentY);
+ currentX = val[k + 0];
+ break;
+ case 'v': // vertical lineto - Draws a vertical line from the current point (r)
+ path.rLineTo(0, val[k + 0]);
+ currentY += val[k + 0];
+ break;
+ case 'V': // vertical lineto - Draws a vertical line from the current point
+ path.lineTo(currentX, val[k + 0]);
+ currentY = val[k + 0];
+ break;
+ case 'c': // curveto - Draws a cubic Bézier curve (relative)
+ path.rCubicTo(val[k + 0], val[k + 1], val[k + 2], val[k + 3],
+ val[k + 4], val[k + 5]);
+
+ ctrlPointX = currentX + val[k + 2];
+ ctrlPointY = currentY + val[k + 3];
+ currentX += val[k + 4];
+ currentY += val[k + 5];
+
+ break;
+ case 'C': // curveto - Draws a cubic Bézier curve
+ path.cubicTo(val[k + 0], val[k + 1], val[k + 2], val[k + 3],
+ val[k + 4], val[k + 5]);
+ currentX = val[k + 4];
+ currentY = val[k + 5];
+ ctrlPointX = val[k + 2];
+ ctrlPointY = val[k + 3];
+ break;
+ case 's': // smooth curveto - Draws a cubic Bézier curve (reflective cp)
+ reflectiveCtrlPointX = 0;
+ reflectiveCtrlPointY = 0;
+ if (previousCmd == 'c' || previousCmd == 's'
+ || previousCmd == 'C' || previousCmd == 'S') {
+ reflectiveCtrlPointX = currentX - ctrlPointX;
+ reflectiveCtrlPointY = currentY - ctrlPointY;
+ }
+ path.rCubicTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+ val[k + 0], val[k + 1],
+ val[k + 2], val[k + 3]);
+
+ ctrlPointX = currentX + val[k + 0];
+ ctrlPointY = currentY + val[k + 1];
+ currentX += val[k + 2];
+ currentY += val[k + 3];
+ break;
+ case 'S': // shorthand/smooth curveto Draws a cubic Bézier curve(reflective cp)
+ reflectiveCtrlPointX = currentX;
+ reflectiveCtrlPointY = currentY;
+ if (previousCmd == 'c' || previousCmd == 's'
+ || previousCmd == 'C' || previousCmd == 'S') {
+ reflectiveCtrlPointX = 2 * currentX - ctrlPointX;
+ reflectiveCtrlPointY = 2 * currentY - ctrlPointY;
+ }
+ path.cubicTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+ val[k + 0], val[k + 1], val[k + 2], val[k + 3]);
+ ctrlPointX = val[k + 0];
+ ctrlPointY = val[k + 1];
+ currentX = val[k + 2];
+ currentY = val[k + 3];
+ break;
+ case 'q': // Draws a quadratic Bézier (relative)
+ path.rQuadTo(val[k + 0], val[k + 1], val[k + 2], val[k + 3]);
+ ctrlPointX = currentX + val[k + 0];
+ ctrlPointY = currentY + val[k + 1];
+ currentX += val[k + 2];
+ currentY += val[k + 3];
+ break;
+ case 'Q': // Draws a quadratic Bézier
+ path.quadTo(val[k + 0], val[k + 1], val[k + 2], val[k + 3]);
+ ctrlPointX = val[k + 0];
+ ctrlPointY = val[k + 1];
+ currentX = val[k + 2];
+ currentY = val[k + 3];
+ break;
+ case 't': // Draws a quadratic Bézier curve(reflective control point)(relative)
+ reflectiveCtrlPointX = 0;
+ reflectiveCtrlPointY = 0;
+ if (previousCmd == 'q' || previousCmd == 't'
+ || previousCmd == 'Q' || previousCmd == 'T') {
+ reflectiveCtrlPointX = currentX - ctrlPointX;
+ reflectiveCtrlPointY = currentY - ctrlPointY;
+ }
+ path.rQuadTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+ val[k + 0], val[k + 1]);
+ ctrlPointX = currentX + reflectiveCtrlPointX;
+ ctrlPointY = currentY + reflectiveCtrlPointY;
+ currentX += val[k + 0];
+ currentY += val[k + 1];
+ break;
+ case 'T': // Draws a quadratic Bézier curve (reflective control point)
+ reflectiveCtrlPointX = currentX;
+ reflectiveCtrlPointY = currentY;
+ if (previousCmd == 'q' || previousCmd == 't'
+ || previousCmd == 'Q' || previousCmd == 'T') {
+ reflectiveCtrlPointX = 2 * currentX - ctrlPointX;
+ reflectiveCtrlPointY = 2 * currentY - ctrlPointY;
+ }
+ path.quadTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+ val[k + 0], val[k + 1]);
+ ctrlPointX = reflectiveCtrlPointX;
+ ctrlPointY = reflectiveCtrlPointY;
+ currentX = val[k + 0];
+ currentY = val[k + 1];
+ break;
+ case 'a': // Draws an elliptical arc
+ // (rx ry x-axis-rotation large-arc-flag sweep-flag x y)
+ drawArc(path,
+ currentX,
+ currentY,
+ val[k + 5] + currentX,
+ val[k + 6] + currentY,
+ val[k + 0],
+ val[k + 1],
+ val[k + 2],
+ val[k + 3] != 0,
+ val[k + 4] != 0);
+ currentX += val[k + 5];
+ currentY += val[k + 6];
+ ctrlPointX = currentX;
+ ctrlPointY = currentY;
+ break;
+ case 'A': // Draws an elliptical arc
+ drawArc(path,
+ currentX,
+ currentY,
+ val[k + 5],
+ val[k + 6],
+ val[k + 0],
+ val[k + 1],
+ val[k + 2],
+ val[k + 3] != 0,
+ val[k + 4] != 0);
+ currentX = val[k + 5];
+ currentY = val[k + 6];
+ ctrlPointX = currentX;
+ ctrlPointY = currentY;
+ break;
+ }
+ previousCmd = cmd;
+ }
+ current[0] = currentX;
+ current[1] = currentY;
+ current[2] = ctrlPointX;
+ current[3] = ctrlPointY;
+ }
+
+ private static void drawArc(Path p,
+ float x0,
+ float y0,
+ float x1,
+ float y1,
+ float a,
+ float b,
+ float theta,
+ boolean isMoreThanHalf,
+ boolean isPositiveArc) {
+
+ /* Convert rotation angle from degrees to radians */
+ double thetaD = Math.toRadians(theta);
+ /* 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;
+
+ /* 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) {
+ Log.w(LOGTAG, " Points are coincident");
+ return; /* Points are coincident */
+ }
+ double disc = 1.0 / dsq - 1.0 / 4.0;
+ if (disc < 0.0) {
+ Log.w(LOGTAG, "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));
+
+ double eta1 = Math.atan2((y1p - cy), (x1p - cx));
+
+ 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;
+
+ 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 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(Path 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 = Math.abs((int) Math.ceil(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.cubicTo((float) q1x,
+ (float) q1y,
+ (float) q2x,
+ (float) q2y,
+ (float) e2x,
+ (float) e2y);
+ eta1 = eta2;
+ e1x = e2x;
+ e1y = e2y;
+ ep1x = ep2x;
+ ep1y = ep2y;
+ }
+ }
+
+ }
+}
generated by cgit v1.1 at 2025-11-28 08:06:38 +0000