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Add bounds checking to nine patch scaling

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bug:17114103

Better handle the case, when scaling the divs in a nine patch, where
divs fall outside of the bounds of the bitmap.

Change-Id: I244b9c45b938c2a15f29e4563a86825ee9439b5f
This commit is contained in:
Chris Craik
2014-08-20 16:31:57 -07:00
parent 3acf66f558
commit bd8db2e87e
1 changed files with 30 additions and 17 deletions
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47
core/jni/android/graphics/BitmapFactory.cpp
View File

@@ -18,6 +18,7 @@
#include <android_runtime/AndroidRuntime.h>
#include <androidfw/Asset.h>
#include <androidfw/ResourceTypes.h>
#include <cutils/compiler.h>
#include <netinet/in.h>
#include <stdio.h>
#include <sys/mman.h>
@@ -87,27 +88,39 @@ static bool optionsJustBounds(JNIEnv* env, jobject options) {
return options != NULL && env->GetBooleanField(options, gOptions_justBoundsFieldID);
}
static void scaleNinePatchChunk(android::Res_png_9patch* chunk, float scale) {
static void scaleDivRange(int32_t* divs, int count, float scale, int maxValue) {
for (int i = 0; i < count; i++) {
divs[i] = int32_t(divs[i] * scale + 0.5f);
if (i > 0 && divs[i] == divs[i - 1]) {
divs[i]++; // avoid collisions
}
}
if (CC_UNLIKELY(divs[count - 1] > maxValue)) {
// if the collision avoidance above put some divs outside the bounds of the bitmap,
// slide outer stretchable divs inward to stay within bounds
int highestAvailable = maxValue;
for (int i = count - 1; i >= 0; i--) {
divs[i] = highestAvailable;
if (i > 0 && divs[i] <= divs[i-1]){
// keep shifting
highestAvailable = divs[i] - 1;
} else {
break;
}
}
}
}
static void scaleNinePatchChunk(android::Res_png_9patch* chunk, float scale,
int scaledWidth, int scaledHeight) {
chunk->paddingLeft = int(chunk->paddingLeft * scale + 0.5f);
chunk->paddingTop = int(chunk->paddingTop * scale + 0.5f);
chunk->paddingRight = int(chunk->paddingRight * scale + 0.5f);
chunk->paddingBottom = int(chunk->paddingBottom * scale + 0.5f);
int32_t* xDivs = chunk->getXDivs();
for (int i = 0; i < chunk->numXDivs; i++) {
xDivs[i] = int32_t(xDivs[i] * scale + 0.5f);
if (i > 0 && xDivs[i] == xDivs[i - 1]) {
xDivs[i]++;
}
}
int32_t* yDivs = chunk->getYDivs();
for (int i = 0; i < chunk->numYDivs; i++) {
yDivs[i] = int32_t(yDivs[i] * scale + 0.5f);
if (i > 0 && yDivs[i] == yDivs[i - 1]) {
yDivs[i]++;
}
}
scaleDivRange(chunk->getXDivs(), chunk->numXDivs, scale, scaledWidth);
scaleDivRange(chunk->getYDivs(), chunk->numYDivs, scale, scaledHeight);
}
static SkColorType colorTypeForScaledOutput(SkColorType colorType) {
@@ -330,7 +343,7 @@ static jobject doDecode(JNIEnv* env, SkStreamRewindable* stream, jobject padding
jbyteArray ninePatchChunk = NULL;
if (peeker.mPatch != NULL) {
if (willScale) {
scaleNinePatchChunk(peeker.mPatch, scale);
scaleNinePatchChunk(peeker.mPatch, scale, scaledWidth, scaledHeight);
}
size_t ninePatchArraySize = peeker.mPatch->serializedSize();