1 /*
2  * Copyright (C) 2011 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 #include "NinePatchPeeker.h"
18 
19 #include <SkBitmap.h>
20 #include <cutils/compiler.h>
21 
22 using namespace android;
23 
24 bool NinePatchPeeker::readChunk(const char tag[], const void* data, size_t length) {
25     if (!strcmp("npTc", tag) && length >= sizeof(Res_png_9patch)) {
26         Res_png_9patch* patch = (Res_png_9patch*) data;
27         size_t patchSize = patch->serializedSize();
28         if (length != patchSize) {
29             return false;
30         }
31         // You have to copy the data because it is owned by the png reader
32         Res_png_9patch* patchNew = (Res_png_9patch*) malloc(patchSize);
33         memcpy(patchNew, patch, patchSize);
34         Res_png_9patch::deserialize(patchNew);
35         patchNew->fileToDevice();
36         free(mPatch);
37         mPatch = patchNew;
38         mPatchSize = patchSize;
39     } else if (!strcmp("npLb", tag) && length == sizeof(int32_t) * 4) {
40         mHasInsets = true;
41         memcpy(&mOpticalInsets, data, sizeof(int32_t) * 4);
42     } else if (!strcmp("npOl", tag) && length == 24) { // 4 int32_ts, 1 float, 1 int32_t sized byte
43         mHasInsets = true;
44         memcpy(&mOutlineInsets, data, sizeof(int32_t) * 4);
45         mOutlineRadius = ((const float*)data)[4];
46         mOutlineAlpha = ((const int32_t*)data)[5] & 0xff;
47     }
48     return true;    // keep on decoding
49 }
50 
51 static void scaleDivRange(int32_t* divs, int count, float scale, int maxValue) {
52     for (int i = 0; i < count; i++) {
53         divs[i] = int32_t(divs[i] * scale + 0.5f);
54         if (i > 0 && divs[i] == divs[i - 1]) {
55             divs[i]++; // avoid collisions
56         }
57     }
58 
59     if (CC_UNLIKELY(divs[count - 1] > maxValue)) {
60         // if the collision avoidance above put some divs outside the bounds of the bitmap,
61         // slide outer stretchable divs inward to stay within bounds
62         int highestAvailable = maxValue;
63         for (int i = count - 1; i >= 0; i--) {
64             divs[i] = highestAvailable;
65             if (i > 0 && divs[i] <= divs[i-1]) {
66                 // keep shifting
67                 highestAvailable = divs[i] - 1;
68             } else {
69                 break;
70             }
71         }
72     }
73 }
74 
75 void NinePatchPeeker::scale(float scaleX, float scaleY, int scaledWidth, int scaledHeight) {
76     if (!mPatch) {
77         return;
78     }
79 
80     // The max value for the divRange is one pixel less than the actual max to ensure that the size
81     // of the last div is not zero. A div of size 0 is considered invalid input and will not render.
82     if (!SkScalarNearlyEqual(scaleX, 1.0f)) {
83         mPatch->paddingLeft   = int(mPatch->paddingLeft   * scaleX + 0.5f);
84         mPatch->paddingRight  = int(mPatch->paddingRight  * scaleX + 0.5f);
85         scaleDivRange(mPatch->getXDivs(), mPatch->numXDivs, scaleX, scaledWidth - 1);
86     }
87 
88     if (!SkScalarNearlyEqual(scaleY, 1.0f)) {
89         mPatch->paddingTop    = int(mPatch->paddingTop    * scaleY + 0.5f);
90         mPatch->paddingBottom = int(mPatch->paddingBottom * scaleY + 0.5f);
91         scaleDivRange(mPatch->getYDivs(), mPatch->numYDivs, scaleY, scaledHeight - 1);
92     }
93 }
94