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 <android_runtime/AndroidRuntime.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 {
PathMeasurePairPathMeasurePair42 PathMeasurePair() {}
PathMeasurePairPathMeasurePair43 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
create(JNIEnv * env,jobject clazz,const SkPath * path,jboolean forceClosed)55 static PathMeasurePair* create(JNIEnv* env, jobject clazz, const SkPath* path, jboolean forceClosed) {
56 return path ? new PathMeasurePair(*path, forceClosed) : new PathMeasurePair;
57 }
58
setPath(JNIEnv * env,jobject clazz,PathMeasurePair * pair,const SkPath * path,jboolean forceClosed)59 static void setPath(JNIEnv* env, jobject clazz, PathMeasurePair* pair, const SkPath* path, jboolean forceClosed) {
60 if (NULL == path) {
61 pair->fPath.reset();
62 } else {
63 pair->fPath = *path;
64 }
65 pair->fMeasure.setPath(&pair->fPath, forceClosed);
66 }
67
getLength(JNIEnv * env,jobject clazz,PathMeasurePair * pair)68 static jfloat getLength(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
69 return SkScalarToFloat(pair->fMeasure.getLength());
70 }
71
convertTwoElemFloatArray(JNIEnv * env,jfloatArray array,const SkScalar src[2])72 static void convertTwoElemFloatArray(JNIEnv* env, jfloatArray array, const SkScalar src[2]) {
73 AutoJavaFloatArray autoArray(env, array, 2);
74 jfloat* ptr = autoArray.ptr();
75 ptr[0] = SkScalarToFloat(src[0]);
76 ptr[1] = SkScalarToFloat(src[1]);
77 }
78
getPosTan(JNIEnv * env,jobject clazz,PathMeasurePair * pair,jfloat dist,jfloatArray pos,jfloatArray tan)79 static jboolean getPosTan(JNIEnv* env, jobject clazz, PathMeasurePair* pair, jfloat dist, jfloatArray pos, jfloatArray tan) {
80 SkScalar tmpPos[2], tmpTan[2];
81 SkScalar* posPtr = pos ? tmpPos : NULL;
82 SkScalar* tanPtr = tan ? tmpTan : NULL;
83
84 if (!pair->fMeasure.getPosTan(SkFloatToScalar(dist), (SkPoint*)posPtr, (SkVector*)tanPtr)) {
85 return false;
86 }
87
88 if (pos) {
89 convertTwoElemFloatArray(env, pos, tmpPos);
90 }
91 if (tan) {
92 convertTwoElemFloatArray(env, tan, tmpTan);
93 }
94 return true;
95 }
96
getMatrix(JNIEnv * env,jobject clazz,PathMeasurePair * pair,jfloat dist,SkMatrix * matrix,int flags)97 static jboolean getMatrix(JNIEnv* env, jobject clazz, PathMeasurePair* pair, jfloat dist,
98 SkMatrix* matrix, int flags) {
99 return pair->fMeasure.getMatrix(SkFloatToScalar(dist), matrix, (SkPathMeasure::MatrixFlags)flags);
100 }
101
getSegment(JNIEnv * env,jobject clazz,PathMeasurePair * pair,jfloat startF,jfloat stopF,SkPath * dst,jboolean startWithMoveTo)102 static jboolean getSegment(JNIEnv* env, jobject clazz, PathMeasurePair* pair, jfloat startF,
103 jfloat stopF, SkPath* dst, jboolean startWithMoveTo) {
104 return pair->fMeasure.getSegment(SkFloatToScalar(startF), SkFloatToScalar(stopF), dst, startWithMoveTo);
105 }
106
isClosed(JNIEnv * env,jobject clazz,PathMeasurePair * pair)107 static jboolean isClosed(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
108 return pair->fMeasure.isClosed();
109 }
110
nextContour(JNIEnv * env,jobject clazz,PathMeasurePair * pair)111 static jboolean nextContour(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
112 return pair->fMeasure.nextContour();
113 }
114
destroy(JNIEnv * env,jobject clazz,PathMeasurePair * pair)115 static void destroy(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
116 delete pair;
117 }
118 };
119
120 static JNINativeMethod methods[] = {
121 {"native_create", "(IZ)I", (void*) SkPathMeasureGlue::create },
122 {"native_setPath", "(IIZ)V", (void*) SkPathMeasureGlue::setPath },
123 {"native_getLength", "(I)F", (void*) SkPathMeasureGlue::getLength },
124 {"native_getPosTan", "(IF[F[F)Z", (void*) SkPathMeasureGlue::getPosTan },
125 {"native_getMatrix", "(IFII)Z", (void*) SkPathMeasureGlue::getMatrix },
126 {"native_getSegment", "(IFFIZ)Z", (void*) SkPathMeasureGlue::getSegment },
127 {"native_isClosed", "(I)Z", (void*) SkPathMeasureGlue::isClosed },
128 {"native_nextContour", "(I)Z", (void*) SkPathMeasureGlue::nextContour },
129 {"native_destroy", "(I)V", (void*) SkPathMeasureGlue::destroy }
130 };
131
register_android_graphics_PathMeasure(JNIEnv * env)132 int register_android_graphics_PathMeasure(JNIEnv* env) {
133 int result = AndroidRuntime::registerNativeMethods(env, "android/graphics/PathMeasure", methods,
134 sizeof(methods) / sizeof(methods[0]));
135 return result;
136 }
137
138 }
139