Update VectorDrawables to use Skia's drawArc implementation.

Using Skia enables drawArc to issue conic draw calls as well as
fixes some of the issues around a scaled path containing a drawArc
being reported as concave.

Bug: 69622768
Test: hwui_unit_tests
Change-Id: I4faab5403ec4ee34e1ad6fae256ae9ad3c6bb05b

1 files changed, 8 insertions, 132 deletions

diff --git a/libs/hwui/utils/VectorDrawableUtils.cpp b/libs/hwui/utils/VectorDrawableUtils.cpp
index 1931d646fa4a..6b8f3154dd36 100644
--- a/libs/hwui/utils/VectorDrawableUtils.cpp
+++ b/libs/hwui/utils/VectorDrawableUtils.cpp
@@ -96,132 +96,6 @@ void VectorDrawableUtils::interpolatePaths(PathData* outData, const PathData& fr
     }
 }
 
-/**
- * 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) {
-        VECTOR_DRAWABLE_LOGD("Points are coincident");
-        return; /* Points are coincident */
-    }
-    double disc = 1.0 / dsq - 1.0 / 4.0;
-    if (disc < 0.0) {
-        VECTOR_DRAWABLE_LOGD("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) {
@@ -424,18 +298,20 @@ void PathResolver::addCommand(SkPath* outPath, char previousCmd, char cmd,
                 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);
+                outPath->arcTo(points->at(k + 0), points->at(k + 1), points->at(k + 2),
+                               (SkPath::ArcSize) (points->at(k + 3) != 0),
+                               (SkPath::Direction) (points->at(k + 4) == 0), 
+                               points->at(k + 5) + currentX, points->at(k + 6) + currentY);
                 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);
+                outPath->arcTo(points->at(k + 0), points->at(k + 1), points->at(k + 2),
+                               (SkPath::ArcSize) (points->at(k + 3) != 0),
+                               (SkPath::Direction) (points->at(k + 4) == 0), 
+                               points->at(k + 5), points->at(k + 6));
                 currentX = points->at(k + 5);
                 currentY = points->at(k + 6);
                 ctrlPointX = currentX;