1 /* libs/android_runtime/android/graphics/PathMeasure.cpp 2 ** 3 ** Copyright 2007, The Android Open Source Project 4 ** 5 ** Licensed under the Apache License, Version 2.0 (the "License"); 6 ** you may not use this file except in compliance with the License. 7 ** You may obtain a copy of the License at 8 ** 9 ** http://www.apache.org/licenses/LICENSE-2.0 10 ** 11 ** Unless required by applicable law or agreed to in writing, software 12 ** distributed under the License is distributed on an "AS IS" BASIS, 13 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 ** See the License for the specific language governing permissions and 15 ** limitations under the License. 16 */ 17 18 #include "jni.h" 19 #include "GraphicsJNI.h" 20 #include <core_jni_helpers.h> 21 22 #include "SkPathMeasure.h" 23 24 /* We declare an explicit pair, so that we don't have to rely on the java 25 client to be sure not to edit the path while we have an active measure 26 object associated with it. 27 28 This costs us the copy of the path, for the sake of not allowing a bad 29 java client to randomly crash (since we can't detect the case where the 30 native path has been modified). 31 32 The C side does have this risk, but it chooses for speed over safety. If it 33 later changes this, and is internally safe from changes to the path, then 34 we can remove this explicit copy from our JNI code. 35 36 Note that we do not have a reference on the java side to the java path. 37 Were we to not need the native copy here, we would want to add a java 38 reference, so that the java path would not get GD'd while the measure object 39 was still alive. 40 */ 41 struct PathMeasurePair { 42 PathMeasurePair() {} 43 PathMeasurePair(const SkPath& path, bool forceClosed) 44 : fPath(path), fMeasure(fPath, forceClosed) {} 45 46 SkPath fPath; // copy of the user's path 47 SkPathMeasure fMeasure; // this guy points to fPath 48 }; 49 50 namespace android { 51 52 class SkPathMeasureGlue { 53 public: 54 55 static jlong create(JNIEnv* env, jobject clazz, jlong pathHandle, 56 jboolean forceClosedHandle) { 57 const SkPath* path = reinterpret_cast<SkPath*>(pathHandle); 58 bool forceClosed = (forceClosedHandle == JNI_TRUE); 59 PathMeasurePair* pair; 60 if(path) 61 pair = new PathMeasurePair(*path, forceClosed); 62 else 63 pair = new PathMeasurePair; 64 return reinterpret_cast<jlong>(pair); 65 } 66 67 static void setPath(JNIEnv* env, jobject clazz, jlong pairHandle, 68 jlong pathHandle, jboolean forceClosedHandle) { 69 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 70 const SkPath* path = reinterpret_cast<SkPath*>(pathHandle); 71 bool forceClosed = (forceClosedHandle == JNI_TRUE); 72 73 if (NULL == path) { 74 pair->fPath.reset(); 75 } else { 76 pair->fPath = *path; 77 } 78 pair->fMeasure.setPath(&pair->fPath, forceClosed); 79 } 80 81 static jfloat getLength(JNIEnv* env, jobject clazz, jlong pairHandle) { 82 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 83 return static_cast<jfloat>(SkScalarToFloat(pair->fMeasure.getLength())); 84 } 85 86 static void convertTwoElemFloatArray(JNIEnv* env, jfloatArray array, const SkScalar src[2]) { 87 AutoJavaFloatArray autoArray(env, array, 2); 88 jfloat* ptr = autoArray.ptr(); 89 ptr[0] = SkScalarToFloat(src[0]); 90 ptr[1] = SkScalarToFloat(src[1]); 91 } 92 93 static jboolean getPosTan(JNIEnv* env, jobject clazz, jlong pairHandle, jfloat dist, jfloatArray pos, jfloatArray tan) { 94 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 95 SkScalar tmpPos[2], tmpTan[2]; 96 SkScalar* posPtr = pos ? tmpPos : NULL; 97 SkScalar* tanPtr = tan ? tmpTan : NULL; 98 99 if (!pair->fMeasure.getPosTan(dist, (SkPoint*)posPtr, (SkVector*)tanPtr)) { 100 return JNI_FALSE; 101 } 102 103 if (pos) { 104 convertTwoElemFloatArray(env, pos, tmpPos); 105 } 106 if (tan) { 107 convertTwoElemFloatArray(env, tan, tmpTan); 108 } 109 return JNI_TRUE; 110 } 111 112 static jboolean getMatrix(JNIEnv* env, jobject clazz, jlong pairHandle, jfloat dist, 113 jlong matrixHandle, jint flags) { 114 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 115 SkMatrix* matrix = reinterpret_cast<SkMatrix*>(matrixHandle); 116 bool result = pair->fMeasure.getMatrix(dist, matrix, (SkPathMeasure::MatrixFlags)flags); 117 return result ? JNI_TRUE : JNI_FALSE; 118 } 119 120 static jboolean getSegment(JNIEnv* env, jobject clazz, jlong pairHandle, jfloat startF, 121 jfloat stopF, jlong dstHandle, jboolean startWithMoveTo) { 122 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 123 SkPath* dst = reinterpret_cast<SkPath*>(dstHandle); 124 bool result = pair->fMeasure.getSegment(startF, stopF, dst, startWithMoveTo); 125 return result ? JNI_TRUE : JNI_FALSE; 126 } 127 128 static jboolean isClosed(JNIEnv* env, jobject clazz, jlong pairHandle) { 129 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 130 bool result = pair->fMeasure.isClosed(); 131 return result ? JNI_TRUE : JNI_FALSE; 132 } 133 134 static jboolean nextContour(JNIEnv* env, jobject clazz, jlong pairHandle) { 135 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 136 bool result = pair->fMeasure.nextContour(); 137 return result ? JNI_TRUE : JNI_FALSE; 138 } 139 140 static void destroy(JNIEnv* env, jobject clazz, jlong pairHandle) { 141 PathMeasurePair* pair = reinterpret_cast<PathMeasurePair*>(pairHandle); 142 delete pair; 143 } 144 }; 145 146 static const JNINativeMethod methods[] = { 147 {"native_create", "(JZ)J", (void*) SkPathMeasureGlue::create }, 148 {"native_setPath", "(JJZ)V", (void*) SkPathMeasureGlue::setPath }, 149 {"native_getLength", "(J)F", (void*) SkPathMeasureGlue::getLength }, 150 {"native_getPosTan", "(JF[F[F)Z", (void*) SkPathMeasureGlue::getPosTan }, 151 {"native_getMatrix", "(JFJI)Z", (void*) SkPathMeasureGlue::getMatrix }, 152 {"native_getSegment", "(JFFJZ)Z", (void*) SkPathMeasureGlue::getSegment }, 153 {"native_isClosed", "(J)Z", (void*) SkPathMeasureGlue::isClosed }, 154 {"native_nextContour", "(J)Z", (void*) SkPathMeasureGlue::nextContour }, 155 {"native_destroy", "(J)V", (void*) SkPathMeasureGlue::destroy } 156 }; 157 158 int register_android_graphics_PathMeasure(JNIEnv* env) { 159 return RegisterMethodsOrDie(env, "android/graphics/PathMeasure", methods, NELEM(methods)); 160 } 161 162 } 163
