diff options
Diffstat (limited to 'jni/filters/contrast.c')
-rw-r--r-- | jni/filters/contrast.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/jni/filters/contrast.c b/jni/filters/contrast.c new file mode 100644 index 000000000..45209c1fb --- /dev/null +++ b/jni/filters/contrast.c @@ -0,0 +1,46 @@ +/* + * Copyright (C) 2012 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "filters.h" + +unsigned char clamp(int c) +{ + int N = 255; + c &= ~(c >> 31); + c -= N; + c &= (c >> 31); + c += N; + return (unsigned char) c; +} + +void JNIFUNCF(ImageFilterContrast, nativeApplyFilter, jobject bitmap, jint width, jint height, jfloat bright) +{ + char* destination = 0; + AndroidBitmap_lockPixels(env, bitmap, (void**) &destination); + unsigned char * rgb = (unsigned char * )destination; + int i; + int len = width * height * 4; + float m = (float)pow(2, bright/100.); + float c = 127-m*127; + + for (i = 0; i < len; i+=4) { + rgb[RED] = clamp((int)(m*rgb[RED]+c)); + rgb[GREEN] = clamp((int)(m*rgb[GREEN]+c)); + rgb[BLUE] = clamp((int)(m*rgb[BLUE]+c)); + } + AndroidBitmap_unlockPixels(env, bitmap); +} + |