1 /* 2 * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved. 3 * Copyright (C) 2008, 2010 Nokia Corporation and/or its subsidiary(-ies) 4 * Copyright (C) 2007 Alp Toker <alp (at) atoker.com> 5 * Copyright (C) 2008 Eric Seidel <eric (at) webkit.org> 6 * Copyright (C) 2008 Dirk Schulze <krit (at) webkit.org> 7 * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved. 8 * Copyright (C) 2012, 2013 Intel Corporation. All rights reserved. 9 * Copyright (C) 2012, 2013 Adobe Systems Incorporated. All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER "AS IS" AND ANY 22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 24 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER BE 25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, 26 * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 28 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR 30 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 31 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include "config.h" 36 #include "core/html/canvas/CanvasPathMethods.h" 37 38 #include "bindings/core/v8/ExceptionState.h" 39 #include "core/dom/ExceptionCode.h" 40 #include "platform/geometry/FloatRect.h" 41 #include "platform/transforms/AffineTransform.h" 42 #include "wtf/MathExtras.h" 43 44 namespace blink { 45 46 void CanvasPathMethods::closePath() 47 { 48 if (m_path.isEmpty()) 49 return; 50 51 FloatRect boundRect = m_path.boundingRect(); 52 if (boundRect.width() || boundRect.height()) 53 m_path.closeSubpath(); 54 } 55 56 void CanvasPathMethods::moveTo(float x, float y) 57 { 58 if (!std::isfinite(x) || !std::isfinite(y)) 59 return; 60 if (!isTransformInvertible()) 61 return; 62 m_path.moveTo(FloatPoint(x, y)); 63 } 64 65 void CanvasPathMethods::lineTo(float x, float y) 66 { 67 if (!std::isfinite(x) || !std::isfinite(y)) 68 return; 69 if (!isTransformInvertible()) 70 return; 71 72 FloatPoint p1 = FloatPoint(x, y); 73 if (!m_path.hasCurrentPoint()) 74 m_path.moveTo(p1); 75 else if (p1 != m_path.currentPoint()) 76 m_path.addLineTo(p1); 77 } 78 79 void CanvasPathMethods::quadraticCurveTo(float cpx, float cpy, float x, float y) 80 { 81 if (!std::isfinite(cpx) || !std::isfinite(cpy) || !std::isfinite(x) || !std::isfinite(y)) 82 return; 83 if (!isTransformInvertible()) 84 return; 85 if (!m_path.hasCurrentPoint()) 86 m_path.moveTo(FloatPoint(cpx, cpy)); 87 88 FloatPoint p1 = FloatPoint(x, y); 89 FloatPoint cp = FloatPoint(cpx, cpy); 90 if (p1 != m_path.currentPoint() || p1 != cp) 91 m_path.addQuadCurveTo(cp, p1); 92 } 93 94 void CanvasPathMethods::bezierCurveTo(float cp1x, float cp1y, float cp2x, float cp2y, float x, float y) 95 { 96 if (!std::isfinite(cp1x) || !std::isfinite(cp1y) || !std::isfinite(cp2x) || !std::isfinite(cp2y) || !std::isfinite(x) || !std::isfinite(y)) 97 return; 98 if (!isTransformInvertible()) 99 return; 100 if (!m_path.hasCurrentPoint()) 101 m_path.moveTo(FloatPoint(cp1x, cp1y)); 102 103 FloatPoint p1 = FloatPoint(x, y); 104 FloatPoint cp1 = FloatPoint(cp1x, cp1y); 105 FloatPoint cp2 = FloatPoint(cp2x, cp2y); 106 if (p1 != m_path.currentPoint() || p1 != cp1 || p1 != cp2) 107 m_path.addBezierCurveTo(cp1, cp2, p1); 108 } 109 110 void CanvasPathMethods::arcTo(float x1, float y1, float x2, float y2, float r, ExceptionState& exceptionState) 111 { 112 if (!std::isfinite(x1) || !std::isfinite(y1) || !std::isfinite(x2) || !std::isfinite(y2) || !std::isfinite(r)) 113 return; 114 115 if (r < 0) { 116 exceptionState.throwDOMException(IndexSizeError, "The radius provided (" + String::number(r) + ") is negative."); 117 return; 118 } 119 120 if (!isTransformInvertible()) 121 return; 122 123 FloatPoint p1 = FloatPoint(x1, y1); 124 FloatPoint p2 = FloatPoint(x2, y2); 125 126 if (!m_path.hasCurrentPoint()) 127 m_path.moveTo(p1); 128 else if (p1 == m_path.currentPoint() || p1 == p2 || !r) 129 lineTo(x1, y1); 130 else 131 m_path.addArcTo(p1, p2, r); 132 } 133 134 namespace { 135 136 float adjustEndAngle(float startAngle, float endAngle, bool anticlockwise) 137 { 138 float newEndAngle = endAngle; 139 /* http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-arc 140 * If the anticlockwise argument is false and endAngle-startAngle is equal to or greater than 2pi, or, 141 * if the anticlockwise argument is true and startAngle-endAngle is equal to or greater than 2pi, 142 * then the arc is the whole circumference of this ellipse, and the point at startAngle along this circle's circumference, 143 * measured in radians clockwise from the ellipse's semi-major axis, acts as both the start point and the end point. 144 */ 145 if (!anticlockwise && endAngle - startAngle >= twoPiFloat) 146 newEndAngle = startAngle + twoPiFloat; 147 else if (anticlockwise && startAngle - endAngle >= twoPiFloat) 148 newEndAngle = startAngle - twoPiFloat; 149 150 /* 151 * Otherwise, the arc is the path along the circumference of this ellipse from the start point to the end point, 152 * going anti-clockwise if the anticlockwise argument is true, and clockwise otherwise. 153 * Since the points are on the ellipse, as opposed to being simply angles from zero, 154 * the arc can never cover an angle greater than 2pi radians. 155 */ 156 /* NOTE: When startAngle = 0, endAngle = 2Pi and anticlockwise = true, the spec does not indicate clearly. 157 * We draw the entire circle, because some web sites use arc(x, y, r, 0, 2*Math.PI, true) to draw circle. 158 * We preserve backward-compatibility. 159 */ 160 else if (!anticlockwise && startAngle > endAngle) 161 newEndAngle = startAngle + (twoPiFloat - fmodf(startAngle - endAngle, twoPiFloat)); 162 else if (anticlockwise && startAngle < endAngle) 163 newEndAngle = startAngle - (twoPiFloat - fmodf(endAngle - startAngle, twoPiFloat)); 164 165 ASSERT(ellipseIsRenderable(startAngle, newEndAngle)); 166 return newEndAngle; 167 } 168 169 inline void lineToFloatPoint(CanvasPathMethods* path, const FloatPoint& p) 170 { 171 path->lineTo(p.x(), p.y()); 172 } 173 174 inline FloatPoint getPointOnEllipse(float radiusX, float radiusY, float theta) 175 { 176 return FloatPoint(radiusX * cosf(theta), radiusY * sinf(theta)); 177 } 178 179 void canonicalizeAngle(float* startAngle, float* endAngle) 180 { 181 // Make 0 <= startAngle < 2*PI 182 float newStartAngle = *startAngle; 183 if (newStartAngle < 0) 184 newStartAngle = twoPiFloat + fmodf(newStartAngle, -twoPiFloat); 185 else 186 newStartAngle = fmodf(newStartAngle, twoPiFloat); 187 188 float delta = newStartAngle - *startAngle; 189 *startAngle = newStartAngle; 190 *endAngle = *endAngle + delta; 191 ASSERT(newStartAngle >= 0 && newStartAngle < twoPiFloat); 192 } 193 194 /* 195 * degenerateEllipse() handles a degenerated ellipse using several lines. 196 * 197 * Let's see a following example: line to ellipse to line. 198 * _--^\ 199 * ( ) 200 * -----( ) 201 * ) 202 * /-------- 203 * 204 * If radiusX becomes zero, the ellipse of the example is degenerated. 205 * _ 206 * // P 207 * // 208 * -----// 209 * / 210 * /-------- 211 * 212 * To draw the above example, need to get P that is a local maximum point. 213 * Angles for P are 0.5Pi and 1.5Pi in the ellipse coordinates. 214 * 215 * If radiusY becomes zero, the result is as follows. 216 * -----__ 217 * --_ 218 * ---------- 219 * ``P 220 * Angles for P are 0 and Pi in the ellipse coordinates. 221 * 222 * To handle both cases, degenerateEllipse() lines to start angle, local maximum points(every 0.5Pi), and end angle. 223 * NOTE: Before ellipse() calls this function, adjustEndAngle() is called, so endAngle - startAngle must be equal to or less than 2Pi. 224 */ 225 void degenerateEllipse(CanvasPathMethods* path, float x, float y, float radiusX, float radiusY, float rotation, float startAngle, float endAngle, bool anticlockwise) 226 { 227 ASSERT(ellipseIsRenderable(startAngle, endAngle)); 228 ASSERT(startAngle >= 0 && startAngle < twoPiFloat); 229 ASSERT((anticlockwise && (startAngle - endAngle) >= 0) || (!anticlockwise && (endAngle - startAngle) >= 0)); 230 231 FloatPoint center(x, y); 232 AffineTransform rotationMatrix; 233 rotationMatrix.rotateRadians(rotation); 234 // 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. 235 lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, startAngle))); 236 if ((!radiusX && !radiusY) || startAngle == endAngle) 237 return; 238 239 if (!anticlockwise) { 240 // startAngle - fmodf(startAngle, piOverTwoFloat) + piOverTwoFloat is the one of (0, 0.5Pi, Pi, 1.5Pi, 2Pi) 241 // that is the closest to startAngle on the clockwise direction. 242 for (float angle = startAngle - fmodf(startAngle, piOverTwoFloat) + piOverTwoFloat; angle < endAngle; angle += piOverTwoFloat) 243 lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, angle))); 244 } else { 245 for (float angle = startAngle - fmodf(startAngle, piOverTwoFloat); angle > endAngle; angle -= piOverTwoFloat) 246 lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, angle))); 247 } 248 249 lineToFloatPoint(path, center + rotationMatrix.mapPoint(getPointOnEllipse(radiusX, radiusY, endAngle))); 250 } 251 252 } // namespace 253 254 void CanvasPathMethods::arc(float x, float y, float radius, float startAngle, float endAngle, bool anticlockwise, ExceptionState& exceptionState) 255 { 256 if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(radius) || !std::isfinite(startAngle) || !std::isfinite(endAngle)) 257 return; 258 259 if (radius < 0) { 260 exceptionState.throwDOMException(IndexSizeError, "The radius provided (" + String::number(radius) + ") is negative."); 261 return; 262 } 263 264 if (!isTransformInvertible()) 265 return; 266 267 if (!radius || startAngle == endAngle) { 268 // The arc is empty but we still need to draw the connecting line. 269 lineTo(x + radius * cosf(startAngle), y + radius * sinf(startAngle)); 270 return; 271 } 272 273 canonicalizeAngle(&startAngle, &endAngle); 274 float adjustedEndAngle = adjustEndAngle(startAngle, endAngle, anticlockwise); 275 m_path.addArc(FloatPoint(x, y), radius, startAngle, adjustedEndAngle, anticlockwise); 276 } 277 278 void CanvasPathMethods::ellipse(float x, float y, float radiusX, float radiusY, float rotation, float startAngle, float endAngle, bool anticlockwise, ExceptionState& exceptionState) 279 { 280 if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(radiusX) || !std::isfinite(radiusY) || !std::isfinite(rotation) || !std::isfinite(startAngle) || !std::isfinite(endAngle)) 281 return; 282 283 if (radiusX < 0) { 284 exceptionState.throwDOMException(IndexSizeError, "The major-axis radius provided (" + String::number(radiusX) + ") is negative."); 285 return; 286 } 287 if (radiusY < 0) { 288 exceptionState.throwDOMException(IndexSizeError, "The minor-axis radius provided (" + String::number(radiusY) + ") is negative."); 289 return; 290 } 291 292 if (!isTransformInvertible()) 293 return; 294 295 canonicalizeAngle(&startAngle, &endAngle); 296 float adjustedEndAngle = adjustEndAngle(startAngle, endAngle, anticlockwise); 297 if (!radiusX || !radiusY || startAngle == adjustedEndAngle) { 298 // The ellipse is empty but we still need to draw the connecting line to start point. 299 degenerateEllipse(this, x, y, radiusX, radiusY, rotation, startAngle, adjustedEndAngle, anticlockwise); 300 return; 301 } 302 303 m_path.addEllipse(FloatPoint(x, y), radiusX, radiusY, rotation, startAngle, adjustedEndAngle, anticlockwise); 304 } 305 306 void CanvasPathMethods::rect(float x, float y, float width, float height) 307 { 308 if (!isTransformInvertible()) 309 return; 310 311 if (!std::isfinite(x) || !std::isfinite(y) || !std::isfinite(width) || !std::isfinite(height)) 312 return; 313 314 if (!width && !height) { 315 m_path.moveTo(FloatPoint(x, y)); 316 return; 317 } 318 319 m_path.addRect(FloatRect(x, y, width, height)); 320 } 321 } 322
