VectorDrawable native rendering - Step 2 of MANY

Introduced PathData in Java, which is effectively a thin layer around the
native instance. PathData holds the verbs and points which is being used
in path morphing/interpolation. The verbs and points can be interpreted
into skia path commands, which is now done in native and therefore saves
a handful of JNI calls during path creation.

Removed the old PathDataNode mechanism and changed the PathEvaluator
to use PathData instead.

Also added tests and a microbench. Also ran CTS tests for VectorDrawable
and AnimatedVectorDrawable, and passed all of the existing tests.

Change-Id: Ia166f5172ff031fe18b154327967f911a62caec1

1 files changed, 491 insertions, 0 deletions

diff --git a/libs/hwui/utils/VectorDrawableUtils.cpp b/libs/hwui/utils/VectorDrawableUtils.cpp
new file mode 100644
index 000000000000..ca75c5945b7f
--- /dev/null
+++ b/libs/hwui/utils/VectorDrawableUtils.cpp
@@ -0,0 +1,491 @@
+/*
+ * 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.
+ */
+
+#include "VectorDrawableUtils.h"
+
+#include "PathParser.h"
+
+#include <math.h>
+#include <utils/Log.h>
+
+namespace android {
+namespace uirenderer {
+
+class PathResolver {
+public:
+    float currentX = 0;
+    float currentY = 0;
+    float ctrlPointX = 0;
+    float ctrlPointY = 0;
+    float currentSegmentStartX = 0;
+    float currentSegmentStartY = 0;
+    void addCommand(SkPath* outPath, char previousCmd,
+            char cmd, const std::vector<float>* points, size_t start, size_t end);
+};
+
+bool VectorDrawableUtils::canMorph(const PathData& morphFrom, const PathData& morphTo) {
+    if (morphFrom.verbs.size() != morphTo.verbs.size()) {
+        return false;
+    }
+
+    for (unsigned int i = 0; i < morphFrom.verbs.size(); i++) {
+        if (morphFrom.verbs[i] != morphTo.verbs[i]
+                ||  morphFrom.verbSizes[i] != morphTo.verbSizes[i]) {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool VectorDrawableUtils::interpolatePathData(PathData* outData, const PathData& morphFrom,
+        const PathData& morphTo, float fraction) {
+    if (!canMorph(morphFrom, morphTo)) {
+        return false;
+    }
+    interpolatePaths(outData, morphFrom, morphTo, fraction);
+    return true;
+}
+
+ /**
+ * Convert an array of PathVerb to Path.
+ */
+void VectorDrawableUtils::verbsToPath(SkPath* outPath, const PathData& data) {
+    PathResolver resolver;
+    char previousCommand = 'm';
+    size_t start = 0;
+    outPath->reset();
+    for (unsigned int i = 0; i < data.verbs.size(); i++) {
+        size_t verbSize = data.verbSizes[i];
+        resolver.addCommand(outPath, previousCommand, data.verbs[i], &data.points, start,
+                start + verbSize);
+        previousCommand = data.verbs[i];
+        start += verbSize;
+    }
+}
+
+/**
+ * The current PathVerb will be interpolated between the
+ * <code>nodeFrom</code> and <code>nodeTo</code> according to the
+ * <code>fraction</code>.
+ *
+ * @param nodeFrom The start value as a PathVerb.
+ * @param nodeTo The end value as a PathVerb
+ * @param fraction The fraction to interpolate.
+ */
+void VectorDrawableUtils::interpolatePaths(PathData* outData,
+        const PathData& from, const PathData& to, float fraction) {
+    outData->points.resize(from.points.size());
+    outData->verbSizes = from.verbSizes;
+    outData->verbs = from.verbs;
+
+    for (size_t i = 0; i < from.points.size(); i++) {
+        outData->points[i] = from.points[i] * (1 - fraction) + to.points[i] * fraction;
+    }
+}
+
+/**
+ * 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
+ */
+static void arcToBezier(SkPath* 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 = ceil(fabs(sweep * 4 / M_PI));
+
+    double eta1 = start;
+    double cosTheta = cos(theta);
+    double sinTheta = sin(theta);
+    double cosEta1 = cos(eta1);
+    double sinEta1 = 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 = sin(eta2);
+        double cosEta2 = 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 = tan((eta2 - eta1) / 2);
+        double alpha =
+                sin(eta2 - eta1) * (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;
+    }
+}
+
+inline double toRadians(float theta) { return theta * M_PI / 180;}
+
+static void drawArc(SkPath* p,
+        float x0,
+        float y0,
+        float x1,
+        float y1,
+        float a,
+        float b,
+        float theta,
+        bool isMoreThanHalf,
+        bool isPositiveArc) {
+
+    /* Convert rotation angle from degrees to radians */
+    double thetaD = toRadians(theta);
+    /* Pre-compute rotation matrix entries */
+    double cosTheta = cos(thetaD);
+    double sinTheta = 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) {
+        ALOGW("Points are coincident");
+        return; /* Points are coincident */
+    }
+    double disc = 1.0 / dsq - 1.0 / 4.0;
+    if (disc < 0.0) {
+        ALOGW("Points are too far apart %f", dsq);
+        float adjust = (float) (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 = 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 = atan2((y0p - cy), (x0p - cx));
+
+    double eta1 = atan2((y1p - cy), (x1p - cx));
+
+    double sweep = (eta1 - eta0);
+    if (isPositiveArc != (sweep >= 0)) {
+        if (sweep > 0) {
+            sweep -= 2 * M_PI;
+        } else {
+            sweep += 2 * M_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);
+}
+
+
+
+// Use the given verb, and points in the range [start, end) to insert a command into the SkPath.
+void PathResolver::addCommand(SkPath* outPath, char previousCmd,
+        char cmd, const std::vector<float>* points, size_t start, size_t end) {
+
+    int incr = 2;
+    float reflectiveCtrlPointX;
+    float reflectiveCtrlPointY;
+
+    switch (cmd) {
+    case 'z':
+    case 'Z':
+        outPath->close();
+        // Path is closed here, but we need to move the pen to the
+        // closed position. So we cache the segment's starting position,
+        // and restore it here.
+        currentX = currentSegmentStartX;
+        currentY = currentSegmentStartY;
+        ctrlPointX = currentSegmentStartX;
+        ctrlPointY = currentSegmentStartY;
+        outPath->moveTo(currentX, currentY);
+        break;
+    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 (unsigned int k = start; k < end; k += incr) {
+        switch (cmd) {
+        case 'm': // moveto - Start a new sub-path (relative)
+            currentX += points->at(k + 0);
+            currentY += points->at(k + 1);
+            if (k > start) {
+                // According to the spec, if a moveto is followed by multiple
+                // pairs of coordinates, the subsequent pairs are treated as
+                // implicit lineto commands.
+                outPath->rLineTo(points->at(k + 0), points->at(k + 1));
+            } else {
+                outPath->rMoveTo(points->at(k + 0), points->at(k + 1));
+                currentSegmentStartX = currentX;
+                currentSegmentStartY = currentY;
+            }
+            break;
+        case 'M': // moveto - Start a new sub-path
+            currentX = points->at(k + 0);
+            currentY = points->at(k + 1);
+            if (k > start) {
+                // According to the spec, if a moveto is followed by multiple
+                // pairs of coordinates, the subsequent pairs are treated as
+                // implicit lineto commands.
+                outPath->lineTo(points->at(k + 0), points->at(k + 1));
+            } else {
+                outPath->moveTo(points->at(k + 0), points->at(k + 1));
+                currentSegmentStartX = currentX;
+                currentSegmentStartY = currentY;
+            }
+            break;
+        case 'l': // lineto - Draw a line from the current point (relative)
+            outPath->rLineTo(points->at(k + 0), points->at(k + 1));
+            currentX += points->at(k + 0);
+            currentY += points->at(k + 1);
+            break;
+        case 'L': // lineto - Draw a line from the current point
+            outPath->lineTo(points->at(k + 0), points->at(k + 1));
+            currentX = points->at(k + 0);
+            currentY = points->at(k + 1);
+            break;
+        case 'h': // horizontal lineto - Draws a horizontal line (relative)
+            outPath->rLineTo(points->at(k + 0), 0);
+            currentX += points->at(k + 0);
+            break;
+        case 'H': // horizontal lineto - Draws a horizontal line
+            outPath->lineTo(points->at(k + 0), currentY);
+            currentX = points->at(k + 0);
+            break;
+        case 'v': // vertical lineto - Draws a vertical line from the current point (r)
+            outPath->rLineTo(0, points->at(k + 0));
+            currentY += points->at(k + 0);
+            break;
+        case 'V': // vertical lineto - Draws a vertical line from the current point
+            outPath->lineTo(currentX, points->at(k + 0));
+            currentY = points->at(k + 0);
+            break;
+        case 'c': // curveto - Draws a cubic Bézier curve (relative)
+            outPath->rCubicTo(points->at(k + 0), points->at(k + 1), points->at(k + 2), points->at(k + 3),
+                    points->at(k + 4), points->at(k + 5));
+
+            ctrlPointX = currentX + points->at(k + 2);
+            ctrlPointY = currentY + points->at(k + 3);
+            currentX += points->at(k + 4);
+            currentY += points->at(k + 5);
+
+            break;
+        case 'C': // curveto - Draws a cubic Bézier curve
+            outPath->cubicTo(points->at(k + 0), points->at(k + 1), points->at(k + 2), points->at(k + 3),
+                    points->at(k + 4), points->at(k + 5));
+            currentX = points->at(k + 4);
+            currentY = points->at(k + 5);
+            ctrlPointX = points->at(k + 2);
+            ctrlPointY = points->at(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;
+            }
+            outPath->rCubicTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+                    points->at(k + 0), points->at(k + 1),
+                    points->at(k + 2), points->at(k + 3));
+            ctrlPointX = currentX + points->at(k + 0);
+            ctrlPointY = currentY + points->at(k + 1);
+            currentX += points->at(k + 2);
+            currentY += points->at(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;
+            }
+            outPath->cubicTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+                    points->at(k + 0), points->at(k + 1), points->at(k + 2), points->at(k + 3));
+            ctrlPointX = points->at(k + 0);
+            ctrlPointY = points->at(k + 1);
+            currentX = points->at(k + 2);
+            currentY = points->at(k + 3);
+            break;
+        case 'q': // Draws a quadratic Bézier (relative)
+            outPath->rQuadTo(points->at(k + 0), points->at(k + 1), points->at(k + 2), points->at(k + 3));
+            ctrlPointX = currentX + points->at(k + 0);
+            ctrlPointY = currentY + points->at(k + 1);
+            currentX += points->at(k + 2);
+            currentY += points->at(k + 3);
+            break;
+        case 'Q': // Draws a quadratic Bézier
+            outPath->quadTo(points->at(k + 0), points->at(k + 1), points->at(k + 2), points->at(k + 3));
+            ctrlPointX = points->at(k + 0);
+            ctrlPointY = points->at(k + 1);
+            currentX = points->at(k + 2);
+            currentY = points->at(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;
+            }
+            outPath->rQuadTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+                    points->at(k + 0), points->at(k + 1));
+            ctrlPointX = currentX + reflectiveCtrlPointX;
+            ctrlPointY = currentY + reflectiveCtrlPointY;
+            currentX += points->at(k + 0);
+            currentY += points->at(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;
+            }
+            outPath->quadTo(reflectiveCtrlPointX, reflectiveCtrlPointY,
+                    points->at(k + 0), points->at(k + 1));
+            ctrlPointX = reflectiveCtrlPointX;
+            ctrlPointY = reflectiveCtrlPointY;
+            currentX = points->at(k + 0);
+            currentY = points->at(k + 1);
+            break;
+        case 'a': // Draws an elliptical arc
+            // (rx ry x-axis-rotation large-arc-flag sweep-flag x y)
+            drawArc(outPath,
+                    currentX,
+                    currentY,
+                    points->at(k + 5) + currentX,
+                    points->at(k + 6) + currentY,
+                    points->at(k + 0),
+                    points->at(k + 1),
+                    points->at(k + 2),
+                    points->at(k + 3) != 0,
+                    points->at(k + 4) != 0);
+            currentX += points->at(k + 5);
+            currentY += points->at(k + 6);
+            ctrlPointX = currentX;
+            ctrlPointY = currentY;
+            break;
+        case 'A': // Draws an elliptical arc
+            drawArc(outPath,
+                    currentX,
+                    currentY,
+                    points->at(k + 5),
+                    points->at(k + 6),
+                    points->at(k + 0),
+                    points->at(k + 1),
+                    points->at(k + 2),
+                    points->at(k + 3) != 0,
+                    points->at(k + 4) != 0);
+            currentX = points->at(k + 5);
+            currentY = points->at(k + 6);
+            ctrlPointX = currentX;
+            ctrlPointY = currentY;
+            break;
+        default:
+            LOG_ALWAYS_FATAL("Unsupported command: %c", cmd);
+            break;
+        }
+        previousCmd = cmd;
+    }
+}
+
+} // namespace uirenderer
+} // namespace android