/* * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved. * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies) * Copyright (C) 2007 Alp Toker * Copyright (C) 2008 Eric Seidel * Copyright (C) 2008 Dirk Schulze * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved. * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved. * Copyright (C) 2012, 2013 Adobe Systems Incorporated. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include "sky/engine/config.h" #include "sky/engine/core/html/canvas/CanvasPathMethods.h" #include "sky/engine/bindings/exception_state.h" #include "sky/engine/core/dom/ExceptionCode.h" #include "sky/engine/platform/geometry/FloatRect.h" #include "sky/engine/platform/transforms/AffineTransform.h" #include "sky/engine/wtf/MathExtras.h" namespace blink { void CanvasPathMethods::closePath() { if (m_path.isEmpty()) return; FloatRect boundRect = m_path.boundingRect(); if (boundRect.width() || boundRect.height()) m_path.closeSubpath(); } void CanvasPathMethods::moveTo(float x, float y) { if (!std::isfinite(x) || !std::isfinite(y)) return; if (!isTransformInvertible()) return; m_path.moveTo(FloatPoint(x, y)); } void CanvasPathMethods::lineTo(float x, float y) { if (!std::isfinite(x) || !std::isfinite(y)) return; if (!isTransformInvertible()) return; FloatPoint p1 = FloatPoint(x, y); if (!m_path.hasCurrentPoint()) m_path.moveTo(p1); else if (p1 != m_path.currentPoint()) m_path.addLineTo(p1); } void CanvasPathMethods::quadraticCurveTo(float cpx, float cpy, float x, float y) { if (!std::isfinite(cpx) || !std::isfinite(cpy) || !std::isfinite(x) || !std::isfinite(y)) return; if (!isTransformInvertible()) return; if (!m_path.hasCurrentPoint()) m_path.moveTo(FloatPoint(cpx, cpy)); FloatPoint p1 = FloatPoint(x, y); FloatPoint cp = FloatPoint(cpx, cpy); if (p1 != m_path.currentPoint() || p1 != cp) m_path.addQuadCurveTo(cp, p1); } void CanvasPathMethods::bezierCurveTo(float cp1x, float cp1y, float cp2x, float cp2y, float x, float y) { if (!std::isfinite(cp1x) || !std::isfinite(cp1y) || !std::isfinite(cp2x) || !std::isfinite(cp2y) || !std::isfinite(x) || !std::isfinite(y)) return; if (!isTransformInvertible()) return; if (!m_path.hasCurrentPoint()) m_path.moveTo(FloatPoint(cp1x, cp1y)); FloatPoint p1 = FloatPoint(x, y); FloatPoint cp1 = FloatPoint(cp1x, cp1y); FloatPoint cp2 = FloatPoint(cp2x, cp2y); if (p1 != m_path.currentPoint() || p1 != cp1 || p1 != cp2) m_path.addBezierCurveTo(cp1, cp2, p1); } void CanvasPathMethods::arcTo(float x1, float y1, float x2, float y2, float r, ExceptionState& exceptionState) { if (!std::isfinite(x1) || !std::isfinite(y1) || !std::isfinite(x2) || !std::isfinite(y2) || !std::isfinite(r)) return; if (r < 0) { exceptionState.ThrowDOMException(IndexSizeError, "The radius provided (" + String::number(r) + ") is negative."); return; } if (!isTransformInvertible()) return; FloatPoint p1 = FloatPoint(x1, y1); FloatPoint p2 = FloatPoint(x2, y2); if (!m_path.hasCurrentPoint()) m_path.moveTo(p1); else if (p1 == m_path.currentPoint() || p1 == p2 || !r) lineTo(x1, y1); else m_path.addArcTo(p1, p2, r); } namespace { float adjustEndAngle(float startAngle, float endAngle, bool anticlockwise) { float newEndAngle = endAngle; /* http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-arc * If the anticlockwise argument is false and endAngle-startAngle is equal to or greater than 2pi, or, * if the anticlockwise argument is true and startAngle-endAngle is equal to or greater than 2pi, * then the arc is the whole circumference of this ellipse, and the point at startAngle along this circle's circumference, * measured in radians clockwise from the ellipse's semi-major axis, acts as both the start point and the end point. */ if (!anticlockwise && endAngle - startAngle >= twoPiFloat) newEndAngle = startAngle + twoPiFloat; else if (anticlockwise && startAngle - endAngle >= twoPiFloat) newEndAngle = startAngle - twoPiFloat; /* * Otherwise, the arc is the path along the circumference of this ellipse from the start point to the end point, * going anti-clockwise if the anticlockwise argument is true, and clockwise otherwise. * Since the points are on the ellipse, as opposed to being simply angles from zero, * the arc can never cover an angle greater than 2pi radians. */ /* NOTE: When startAngle = 0, endAngle = 2Pi and anticlockwise = true, the spec does not indicate clearly. * We draw the entire circle, because some web sites use arc(x, y, r, 0, 2*Math.PI, true) to draw circle. * We preserve backward-compatibility. */ else if (!anticlockwise && startAngle > endAngle) newEndAngle = startAngle + (twoPiFloat - fmodf(startAngle - endAngle, twoPiFloat)); else if (anticlockwise && startAngle < endAngle) newEndAngle = startAngle - (twoPiFloat - fmodf(endAngle - startAngle, twoPiFloat)); ASSERT(ellipseIsRenderable(startAngle, newEndAngle)); return newEndAngle; } inline void lineToFloatPoint(CanvasPathMethods* path, const FloatPoint& p) { path->lineTo(p.x(), p.y()); } inline FloatPoint getPointOnEllipse(float radiusX, float radiusY, float theta) { return FloatPoint(radiusX * cosf(theta), radiusY * sinf(theta)); } void canonicalizeAngle(float* startAngle, float* endAngle) { // Make 0 <= startAngle < 2*PI float newStartAngle = *startAngle; if (newStartAngle < 0) newStartAngle = twoPiFloat + fmodf(newStartAngle, -twoPiFloat); else newStartAngle = fmodf(newStartAngle, twoPiFloat); float delta = newStartAngle - *startAngle; *startAngle = newStartAngle; *endAngle = *endAngle + delta; ASSERT(newStartAngle >= 0 && newStartAngle < twoPiFloat); } /* * degenerateEllipse() handles a degenerated ellipse using several lines. * * Let's see a following example: line to ellipse to line. * _--^\ * ( ) * -----( ) * ) * /-------- * * If radiusX becomes zero, the ellipse of the example is degenerated. * _ * // P * // * -----// * / * /-------- * * To draw the above example, need to get P that is a local maximum point. * Angles for P are 0.5Pi and 1.5Pi in the ellipse coordinates. * * If radiusY becomes zero, the result is as follows. * -----__ * --_ * ---------- * ``P * Angles for P are 0 and Pi in the ellipse coordinates. * * To handle both cases, degenerateEllipse() lines to start angle, local maximum points(every 0.5Pi), and end angle. * NOTE: Before ellipse() calls this function, adjustEndAngle() is called, so endAngle - startAngle must be equal to or less than 2Pi. */ void degenerateEllipse(CanvasPathMethods* path, float x, float y, float radiusX, float radiusY, float rotation, float startAngle, float endAngle, bool anticlockwise) { ASSERT(ellipseIsRenderable(startAngle, endAngle)); ASSERT(startAngle >= 0 && startAngle < twoPiFloat); ASSERT((anticlockwise && (startAngle - endAngle) >= 0) || (!anticlockwise && (endAngle - startAngle) >= 0)); FloatPoint center(x, y); AffineTransform rotationMatrix; rotationMatrix.rotateRadians(rotation); // First, if the object's path has any subpaths, then the method must add a straight line from the last point in the subpath to the start point of the arc. lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, startAngle))); if ((!radiusX && !radiusY) || startAngle == endAngle) return; if (!anticlockwise) { // startAngle - fmodf(startAngle, piOverTwoFloat) + piOverTwoFloat is the one of (0, 0.5Pi, Pi, 1.5Pi, 2Pi) // that is the closest to startAngle on the clockwise direction. for (float angle = startAngle - fmodf(startAngle, piOverTwoFloat) + piOverTwoFloat; angle < endAngle; angle += piOverTwoFloat) lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, angle))); } else { for (float angle = startAngle - fmodf(startAngle, piOverTwoFloat); angle > endAngle; angle -= piOverTwoFloat) lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, angle))); } lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, endAngle))); } } // namespace void CanvasPathMethods::arc(float x, float y, float radius, float startAngle, float endAngle, bool anticlockwise, ExceptionState& exceptionState) { if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(radius) || !std::isfinite(startAngle) || !std::isfinite(endAngle)) return; if (radius < 0) { exceptionState.ThrowDOMException(IndexSizeError, "The radius provided (" + String::number(radius) + ") is negative."); return; } if (!isTransformInvertible()) return; if (!radius || startAngle == endAngle) { // The arc is empty but we still need to draw the connecting line. lineTo(x + radius * cosf(startAngle), y + radius * sinf(startAngle)); return; } canonicalizeAngle(&startAngle, &endAngle); float adjustedEndAngle = adjustEndAngle(startAngle, endAngle, anticlockwise); m_path.addArc(FloatPoint(x, y), radius, startAngle, adjustedEndAngle, anticlockwise); } void CanvasPathMethods::ellipse(float x, float y, float radiusX, float radiusY, float rotation, float startAngle, float endAngle, bool anticlockwise, ExceptionState& exceptionState) { if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(radiusX) || !std::isfinite(radiusY) || !std::isfinite(rotation) || !std::isfinite(startAngle) || !std::isfinite(endAngle)) return; if (radiusX < 0) { exceptionState.ThrowDOMException(IndexSizeError, "The major-axis radius provided (" + String::number(radiusX) + ") is negative."); return; } if (radiusY < 0) { exceptionState.ThrowDOMException(IndexSizeError, "The minor-axis radius provided (" + String::number(radiusY) + ") is negative."); return; } if (!isTransformInvertible()) return; canonicalizeAngle(&startAngle, &endAngle); float adjustedEndAngle = adjustEndAngle(startAngle, endAngle, anticlockwise); if (!radiusX || !radiusY || startAngle == adjustedEndAngle) { // The ellipse is empty but we still need to draw the connecting line to start point. degenerateEllipse(this, x, y, radiusX, radiusY, rotation, startAngle, adjustedEndAngle, anticlockwise); return; } m_path.addEllipse(FloatPoint(x, y), radiusX, radiusY, rotation, startAngle, adjustedEndAngle, anticlockwise); } void CanvasPathMethods::rect(float x, float y, float width, float height) { if (!isTransformInvertible()) return; if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(width) || !std::isfinite(height)) return; if (!width && !height) { m_path.moveTo(FloatPoint(x, y)); return; } m_path.addRect(FloatRect(x, y, width, height)); } }