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*/
41struct 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
50namespace android {
51
52class SkPathMeasureGlue {
53public:
54
55    static PathMeasurePair* create(JNIEnv* env, jobject clazz, const SkPath* path, jboolean forceClosed) {
56        return path ? new PathMeasurePair(*path, forceClosed) : new PathMeasurePair;
57    }
58
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
68    static jfloat getLength(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
69        return SkScalarToFloat(pair->fMeasure.getLength());
70    }
71
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
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
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
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
107    static jboolean isClosed(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
108        return pair->fMeasure.isClosed();
109    }
110
111    static jboolean nextContour(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
112        return pair->fMeasure.nextContour();
113    }
114
115    static void destroy(JNIEnv* env, jobject clazz, PathMeasurePair* pair) {
116        delete pair;
117    }
118};
119
120static 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
132int 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