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這篇文章將為大家詳細(xì)講解有關(guān)如何進(jìn)行圖片JNI C++\Java高斯模糊的實(shí)現(xiàn)，文章內(nèi)容質(zhì)量較高，因此小編分享給大家做個(gè)參考，希望大家閱讀完這篇文章后對(duì)相關(guān)知識(shí)有一定的了解。
說(shuō)明：其中代碼大部分來(lái)源于網(wǎng)絡(luò)，不過(guò)都是開源的。
最原始的代碼：
// The Stack Blur Algorithm was invented by Mario Klingemann,
// mario@quasimondo.com and described here:
// http://incubator.quasimondo.com/processing/fast_blur_deluxe.php
// This is C++ RGBA (32 bit color) multi-threaded version
// by Victor Laskin (victor.laskin@gmail.com)
// More details: http://vitiy.info/stackblur-algorithm-multi-threaded-blur-for-cpp
// This code is using MVThread class from my cross-platform framework
// You can exchange it with any thread implementation you like
// -------------------------------------- stackblur ----------------------------------------->
static unsigned short const stackblur_mul[255] =
{
512,512,456,512,328,456,335,512,405,328,271,456,388,335,292,512,
454,405,364,328,298,271,496,456,420,388,360,335,312,292,273,512,
482,454,428,405,383,364,345,328,312,298,284,271,259,496,475,456,
437,420,404,388,374,360,347,335,323,312,302,292,282,273,265,512,
497,482,468,454,441,428,417,405,394,383,373,364,354,345,337,328,
320,312,305,298,291,284,278,271,265,259,507,496,485,475,465,456,
446,437,428,420,412,404,396,388,381,374,367,360,354,347,341,335,
329,323,318,312,307,302,297,292,287,282,278,273,269,265,261,512,
505,497,489,482,475,468,461,454,447,441,435,428,422,417,411,405,
399,394,389,383,378,373,368,364,359,354,350,345,341,337,332,328,
324,320,316,312,309,305,301,298,294,291,287,284,281,278,274,271,
268,265,262,259,257,507,501,496,491,485,480,475,470,465,460,456,
451,446,442,437,433,428,424,420,416,412,408,404,400,396,392,388,
385,381,377,374,370,367,363,360,357,354,350,347,344,341,338,335,
332,329,326,323,320,318,315,312,310,307,304,302,299,297,294,292,
289,287,285,282,280,278,275,273,271,269,267,265,263,261,259
};
static unsigned char const stackblur_shr[255] =
{
9, 11, 12, 13, 13, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17,
17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 19,
19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20,
20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24
};
/// Stackblur algorithm body
void stackblurJob(unsigned char* src, ///< input image data
unsigned int w, ///< image width
unsigned int h, ///< image height
unsigned int radius, ///< blur intensity (should be in 2..254 range)
int cores, ///< total number of working threads
int core, ///< current thread number
int step, ///< step of processing (1,2)
unsigned char* stack ///< stack buffer
)
{
unsigned int x, y, xp, yp, i;
unsigned int sp;
unsigned int stack_start;
unsigned char* stack_ptr;
unsigned char* src_ptr;
unsigned char* dst_ptr;
unsigned long sum_r;
unsigned long sum_g;
unsigned long sum_b;
unsigned long sum_a;
unsigned long sum_in_r;
unsigned long sum_in_g;
unsigned long sum_in_b;
unsigned long sum_in_a;
unsigned long sum_out_r;
unsigned long sum_out_g;
unsigned long sum_out_b;
unsigned long sum_out_a;
unsigned int wm = w - 1;
unsigned int hm = h - 1;
unsigned int w4 = w * 4;
unsigned int div = (radius * 2) + 1;
unsigned int mul_sum = stackblur_mul[radius];
unsigned char shr_sum = stackblur_shr[radius];
if (step == 1)
{
int minY = core * h / cores;
int maxY = (core + 1) * h / cores;
for(y = minY; y < maxY; y++)
{
sum_r = sum_g = sum_b = sum_a =
sum_in_r = sum_in_g = sum_in_b = sum_in_a =
sum_out_r = sum_out_g = sum_out_b = sum_out_a = 0;
src_ptr = src + w4 * y; // start of line (0,y)
for(i = 0; i <= radius; i++)
{
stack_ptr = &stack[ 4 * i ];
stack_ptr[0] = src_ptr[0];
stack_ptr[1] = src_ptr[1];
stack_ptr[2] = src_ptr[2];
stack_ptr[3] = src_ptr[3];
sum_r += src_ptr[0] * (i + 1);
sum_g += src_ptr[1] * (i + 1);
sum_b += src_ptr[2] * (i + 1);
sum_a += src_ptr[3] * (i + 1);
sum_out_r += src_ptr[0];
sum_out_g += src_ptr[1];
sum_out_b += src_ptr[2];
sum_out_a += src_ptr[3];
}
for(i = 1; i <= radius; i++)
{
if (i <= wm) src_ptr += 4;
stack_ptr = &stack[ 4 * (i + radius) ];
stack_ptr[0] = src_ptr[0];
stack_ptr[1] = src_ptr[1];
stack_ptr[2] = src_ptr[2];
stack_ptr[3] = src_ptr[3];
sum_r += src_ptr[0] * (radius + 1 - i);
sum_g += src_ptr[1] * (radius + 1 - i);
sum_b += src_ptr[2] * (radius + 1 - i);
sum_a += src_ptr[3] * (radius + 1 - i);
sum_in_r += src_ptr[0];
sum_in_g += src_ptr[1];
sum_in_b += src_ptr[2];
sum_in_a += src_ptr[3];
}
sp = radius;
xp = radius;
if (xp > wm) xp = wm;
src_ptr = src + 4 * (xp + y * w); // img.pix_ptr(xp, y);
dst_ptr = src + y * w4; // img.pix_ptr(0, y);
for(x = 0; x < w; x++)
{
dst_ptr[0] = (sum_r * mul_sum) >> shr_sum;
dst_ptr[1] = (sum_g * mul_sum) >> shr_sum;
dst_ptr[2] = (sum_b * mul_sum) >> shr_sum;
dst_ptr[3] = (sum_a * mul_sum) >> shr_sum;
dst_ptr += 4;
sum_r -= sum_out_r;
sum_g -= sum_out_g;
sum_b -= sum_out_b;
sum_a -= sum_out_a;
stack_start = sp + div - radius;
if (stack_start >= div) stack_start -= div;
stack_ptr = &stack[4 * stack_start];
sum_out_r -= stack_ptr[0];
sum_out_g -= stack_ptr[1];
sum_out_b -= stack_ptr[2];
sum_out_a -= stack_ptr[3];
if(xp < wm)
{
src_ptr += 4;
++xp;
}
stack_ptr[0] = src_ptr[0];
stack_ptr[1] = src_ptr[1];
stack_ptr[2] = src_ptr[2];
stack_ptr[3] = src_ptr[3];
sum_in_r += src_ptr[0];
sum_in_g += src_ptr[1];
sum_in_b += src_ptr[2];
sum_in_a += src_ptr[3];
sum_r += sum_in_r;
sum_g += sum_in_g;
sum_b += sum_in_b;
sum_a += sum_in_a;
++sp;
if (sp >= div) sp = 0;
stack_ptr = &stack[sp*4];
sum_out_r += stack_ptr[0];
sum_out_g += stack_ptr[1];
sum_out_b += stack_ptr[2];
sum_out_a += stack_ptr[3];
sum_in_r -= stack_ptr[0];
sum_in_g -= stack_ptr[1];
sum_in_b -= stack_ptr[2];
sum_in_a -= stack_ptr[3];
}
}
}
// step 2
if (step == 2)
{
int minX = core * w / cores;
int maxX = (core + 1) * w / cores;
for(x = minX; x < maxX; x++)
{
sum_r = sum_g = sum_b = sum_a =
sum_in_r = sum_in_g = sum_in_b = sum_in_a =
sum_out_r = sum_out_g = sum_out_b = sum_out_a = 0;
src_ptr = src + 4 * x; // x,0
for(i = 0; i <= radius; i++)
{
stack_ptr = &stack[i * 4];
stack_ptr[0] = src_ptr[0];
stack_ptr[1] = src_ptr[1];
stack_ptr[2] = src_ptr[2];
stack_ptr[3] = src_ptr[3];
sum_r += src_ptr[0] * (i + 1);
sum_g += src_ptr[1] * (i + 1);
sum_b += src_ptr[2] * (i + 1);
sum_a += src_ptr[3] * (i + 1);
sum_out_r += src_ptr[0];
sum_out_g += src_ptr[1];
sum_out_b += src_ptr[2];
sum_out_a += src_ptr[3];
}
for(i = 1; i <= radius; i++)
{
if(i <= hm) src_ptr += w4; // +stride
stack_ptr = &stack[4 * (i + radius)];
stack_ptr[0] = src_ptr[0];
stack_ptr[1] = src_ptr[1];
stack_ptr[2] = src_ptr[2];
stack_ptr[3] = src_ptr[3];
sum_r += src_ptr[0] * (radius + 1 - i);
sum_g += src_ptr[1] * (radius + 1 - i);
sum_b += src_ptr[2] * (radius + 1 - i);
sum_a += src_ptr[3] * (radius + 1 - i);
sum_in_r += src_ptr[0];
sum_in_g += src_ptr[1];
sum_in_b += src_ptr[2];
sum_in_a += src_ptr[3];
}
sp = radius;
yp = radius;
if (yp > hm) yp = hm;
src_ptr = src + 4 * (x + yp * w); // img.pix_ptr(x, yp);
dst_ptr = src + 4 * x; // img.pix_ptr(x, 0);
for(y = 0; y < h; y++)
{
dst_ptr[0] = (sum_r * mul_sum) >> shr_sum;
dst_ptr[1] = (sum_g * mul_sum) >> shr_sum;
dst_ptr[2] = (sum_b * mul_sum) >> shr_sum;
dst_ptr[3] = (sum_a * mul_sum) >> shr_sum;
dst_ptr += w4;
sum_r -= sum_out_r;
sum_g -= sum_out_g;
sum_b -= sum_out_b;
sum_a -= sum_out_a;
stack_start = sp + div - radius;
if(stack_start >= div) stack_start -= div;
stack_ptr = &stack[4 * stack_start];
sum_out_r -= stack_ptr[0];
sum_out_g -= stack_ptr[1];
sum_out_b -= stack_ptr[2];
sum_out_a -= stack_ptr[3];
if(yp < hm)
{
src_ptr += w4; // stride
++yp;
}
stack_ptr[0] = src_ptr[0];
stack_ptr[1] = src_ptr[1];
stack_ptr[2] = src_ptr[2];
stack_ptr[3] = src_ptr[3];
sum_in_r += src_ptr[0];
sum_in_g += src_ptr[1];
sum_in_b += src_ptr[2];
sum_in_a += src_ptr[3];
sum_r += sum_in_r;
sum_g += sum_in_g;
sum_b += sum_in_b;
sum_a += sum_in_a;
++sp;
if (sp >= div) sp = 0;
stack_ptr = &stack[sp*4];
sum_out_r += stack_ptr[0];
sum_out_g += stack_ptr[1];
sum_out_b += stack_ptr[2];
sum_out_a += stack_ptr[3];
sum_in_r -= stack_ptr[0];
sum_in_g -= stack_ptr[1];
sum_in_b -= stack_ptr[2];
sum_in_a -= stack_ptr[3];
}
}
}
}
class MVImageUtilsStackBlurTask : public MVThread
{
public:
unsigned char* src;
unsigned int w;
unsigned int h;
unsigned int radius;
int cores;
int core;
int step;
unsigned char* stack;
inline MVImageUtilsStackBlurTask(unsigned char* src, unsigned int w, unsigned int h, unsigned int radius, int cores, int core, int step, unsigned char* stack)
{
this->src = src;
this->w = w;
this->h = h;
this->radius = radius;
this->cores = cores;
this->core = core;
this->step = step;
this->stack = stack;
}
inline void run()
{
stackblurJob(src, w, h, radius, cores, core, step, stack);
}
};
/// Stackblur algorithm by Mario Klingemann
/// Details here:
/// http://www.quasimondo.com/StackBlurForCanvas/StackBlurDemo.html
/// C++ implemenation base from:
/// https://gist.github.com/benjamin9999/3809142
/// http://www.antigrain.com/__code/include/agg_blur.h.html
/// This version works only with RGBA color
void stackblur(unsigned char* src, ///< input image data
unsigned int w, ///< image width
unsigned int h, ///< image height
unsigned int radius, ///< blur intensity (should be in 2..254 range)
int cores = 1 ///< number of threads (1 - normal single thread)
)
{
if (radius > 254) return;
if (radius < 2) return;
unsigned int div = (radius * 2) + 1;
unsigned char* stack = new unsigned char [div * 4 * cores];
if (cores == 1)
{
// no multithreading
stackblurJob(src, w, h, radius, 1, 0, 1, stack);
stackblurJob(src, w, h, radius, 1, 0, 2, stack);
}
else
{
MVImageUtilsStackBlurTask** workers = new MVImageUtilsStackBlurTask*[cores];
for (int i = 0; i < cores; i++)
{
workers[i] = new MVImageUtilsStackBlurTask(src, w, h, radius, cores, i, 1, stack + div * 4 * i);
workers[i]->start();
}
for (int i = 0; i < cores; i++)
workers[i]->wait();
for (int i = 0; i < cores; i++)
{
workers[i]->step = 2;
workers[i]->start();
}
for (int i = 0; i < cores; i++)
{
workers[i]->wait();
delete workers[i];
}
delete[] workers;
}
delete[] stack;
}這個(gè)是C++的代碼。
在網(wǎng)上發(fā)現(xiàn)了一個(gè)開源的 Android 模糊的例子，其中有該代碼的 Java 版本。
import android.graphics.Bitmap;
import java.util.ArrayList;
import java.util.concurrent.Callable;
class JavaBlurProcess implements BlurProcess {
private static final short[] stackblur_mul = {
512, 512, 456, 512, 328, 456, 335, 512, 405, 328, 271, 456, 388, 335, 292, 512,
454, 405, 364, 328, 298, 271, 496, 456, 420, 388, 360, 335, 312, 292, 273, 512,
482, 454, 428, 405, 383, 364, 345, 328, 312, 298, 284, 271, 259, 496, 475, 456,
437, 420, 404, 388, 374, 360, 347, 335, 323, 312, 302, 292, 282, 273, 265, 512,
497, 482, 468, 454, 441, 428, 417, 405, 394, 383, 373, 364, 354, 345, 337, 328,
320, 312, 305, 298, 291, 284, 278, 271, 265, 259, 507, 496, 485, 475, 465, 456,
446, 437, 428, 420, 412, 404, 396, 388, 381, 374, 367, 360, 354, 347, 341, 335,
329, 323, 318, 312, 307, 302, 297, 292, 287, 282, 278, 273, 269, 265, 261, 512,
505, 497, 489, 482, 475, 468, 461, 454, 447, 441, 435, 428, 422, 417, 411, 405,
399, 394, 389, 383, 378, 373, 368, 364, 359, 354, 350, 345, 341, 337, 332, 328,
324, 320, 316, 312, 309, 305, 301, 298, 294, 291, 287, 284, 281, 278, 274, 271,
268, 265, 262, 259, 257, 507, 501, 496, 491, 485, 480, 475, 470, 465, 460, 456,
451, 446, 442, 437, 433, 428, 424, 420, 416, 412, 408, 404, 400, 396, 392, 388,
385, 381, 377, 374, 370, 367, 363, 360, 357, 354, 350, 347, 344, 341, 338, 335,
332, 329, 326, 323, 320, 318, 315, 312, 310, 307, 304, 302, 299, 297, 294, 292,
289, 287, 285, 282, 280, 278, 275, 273, 271, 269, 267, 265, 263, 261, 259
};
private static final byte[] stackblur_shr = {
9, 11, 12, 13, 13, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 17,
17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 18, 19,
19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 20, 20, 20,
20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 21,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24
};
@Override
public Bitmap blur(Bitmap original, float radius) {
int w = original.getWidth();
int h = original.getHeight();
int[] currentPixels = new int[w * h];
original.getPixels(currentPixels, 0, w, 0, 0, w, h);
int cores = StackBlurManager.EXECUTOR_THREADS;
ArrayList<BlurTask> horizontal = new ArrayList<BlurTask>(cores);
ArrayList<BlurTask> vertical = new ArrayList<BlurTask>(cores);
for (int i = 0; i < cores; i++) {
horizontal.add(new BlurTask(currentPixels, w, h, (int) radius, cores, i, 1));
vertical.add(new BlurTask(currentPixels, w, h, (int) radius, cores, i, 2));
}
try {
StackBlurManager.EXECUTOR.invokeAll(horizontal);
} catch (InterruptedException e) {
return null;
}
try {
StackBlurManager.EXECUTOR.invokeAll(vertical);
} catch (InterruptedException e) {
return null;
}
return Bitmap.createBitmap(currentPixels, w, h, Bitmap.Config.ARGB_8888);
}
private static void blurIteration(int[] src, int w, int h, int radius, int cores, int core, int step) {
int x, y, xp, yp, i;
int sp;
int stack_start;
int stack_i;
int src_i;
int dst_i;
long sum_r, sum_g, sum_b,
sum_in_r, sum_in_g, sum_in_b,
sum_out_r, sum_out_g, sum_out_b;
int wm = w - 1;
int hm = h - 1;
int div = (radius * 2) + 1;
int mul_sum = stackblur_mul[radius];
byte shr_sum = stackblur_shr[radius];
int[] stack = new int[div];
if (step == 1)
{
int minY = core * h / cores;
int maxY = (core + 1) * h / cores;
for(y = minY; y < maxY; y++)
{
sum_r = sum_g = sum_b =
sum_in_r = sum_in_g = sum_in_b =
sum_out_r = sum_out_g = sum_out_b = 0;
src_i = w * y; // start of line (0,y)
for(i = 0; i <= radius; i++)
{
stack_i = i;
stack[stack_i] = src[src_i];
sum_r += ((src[src_i] >>> 16) & 0xff) * (i + 1);
sum_g += ((src[src_i] >>> 8) & 0xff) * (i + 1);
sum_b += (src[src_i] & 0xff) * (i + 1);
sum_out_r += ((src[src_i] >>> 16) & 0xff);
sum_out_g += ((src[src_i] >>> 8) & 0xff);
sum_out_b += (src[src_i] & 0xff);
}
for(i = 1; i <= radius; i++)
{
if (i <= wm) src_i += 1;
stack_i = i + radius;
stack[stack_i] = src[src_i];
sum_r += ((src[src_i] >>> 16) & 0xff) * (radius + 1 - i);
sum_g += ((src[src_i] >>> 8) & 0xff) * (radius + 1 - i);
sum_b += (src[src_i] & 0xff) * (radius + 1 - i);
sum_in_r += ((src[src_i] >>> 16) & 0xff);
sum_in_g += ((src[src_i] >>> 8) & 0xff);
sum_in_b += (src[src_i] & 0xff);
}
sp = radius;
xp = radius;
if (xp > wm) xp = wm;
src_i = xp + y * w; // img.pix_ptr(xp, y);
dst_i = y * w; // img.pix_ptr(0, y);
for(x = 0; x < w; x++)
{
src[dst_i] = (int)
((src[dst_i] & 0xff000000) |
((((sum_r * mul_sum) >>> shr_sum) & 0xff) << 16) |
((((sum_g * mul_sum) >>> shr_sum) & 0xff) << 8) |
((((sum_b * mul_sum) >>> shr_sum) & 0xff)));
dst_i += 1;
sum_r -= sum_out_r;
sum_g -= sum_out_g;
sum_b -= sum_out_b;
stack_start = sp + div - radius;
if (stack_start >= div) stack_start -= div;
stack_i = stack_start;
sum_out_r -= ((stack[stack_i] >>> 16) & 0xff);
sum_out_g -= ((stack[stack_i] >>> 8) & 0xff);
sum_out_b -= (stack[stack_i] & 0xff);
if(xp < wm)
{
src_i += 1;
++xp;
}
stack[stack_i] = src[src_i];
sum_in_r += ((src[src_i] >>> 16) & 0xff);
sum_in_g += ((src[src_i] >>> 8) & 0xff);
sum_in_b += (src[src_i] & 0xff);
sum_r += sum_in_r;
sum_g += sum_in_g;
sum_b += sum_in_b;
++sp;
if (sp >= div) sp = 0;
stack_i = sp;
sum_out_r += ((stack[stack_i] >>> 16) & 0xff);
sum_out_g += ((stack[stack_i] >>> 8) & 0xff);
sum_out_b += (stack[stack_i] & 0xff);
sum_in_r -= ((stack[stack_i] >>> 16) & 0xff);
sum_in_g -= ((stack[stack_i] >>> 8) & 0xff);
sum_in_b -= (stack[stack_i] & 0xff);
}
}
}
// step 2
else if (step == 2)
{
int minX = core * w / cores;
int maxX = (core + 1) * w / cores;
for(x = minX; x < maxX; x++)
{
sum_r = sum_g = sum_b =
sum_in_r = sum_in_g = sum_in_b =
sum_out_r = sum_out_g = sum_out_b = 0;
src_i = x; // x,0
for(i = 0; i <= radius; i++)
{
stack_i = i;
stack[stack_i] = src[src_i];
sum_r += ((src[src_i] >>> 16) & 0xff) * (i + 1);
sum_g += ((src[src_i] >>> 8) & 0xff) * (i + 1);
sum_b += (src[src_i] & 0xff) * (i + 1);
sum_out_r += ((src[src_i] >>> 16) & 0xff);
sum_out_g += ((src[src_i] >>> 8) & 0xff);
sum_out_b += (src[src_i] & 0xff);
}
for(i = 1; i <= radius; i++)
{
if(i <= hm) src_i += w; // +stride
stack_i = i + radius;
stack[stack_i] = src[src_i];
sum_r += ((src[src_i] >>> 16) & 0xff) * (radius + 1 - i);
sum_g += ((src[src_i] >>> 8) & 0xff) * (radius + 1 - i);
sum_b += (src[src_i] & 0xff) * (radius + 1 - i);
sum_in_r += ((src[src_i] >>> 16) & 0xff);
sum_in_g += ((src[src_i] >>> 8) & 0xff);
sum_in_b += (src[src_i] & 0xff);
}
sp = radius;
yp = radius;
if (yp > hm) yp = hm;
src_i = x + yp * w; // img.pix_ptr(x, yp);
dst_i = x; // img.pix_ptr(x, 0);
for(y = 0; y < h; y++)
{
src[dst_i] = (int)
((src[dst_i] & 0xff000000) |
((((sum_r * mul_sum) >>> shr_sum) & 0xff) << 16) |
((((sum_g * mul_sum) >>> shr_sum) & 0xff) << 8) |
((((sum_b * mul_sum) >>> shr_sum) & 0xff)));
dst_i += w;
sum_r -= sum_out_r;
sum_g -= sum_out_g;
sum_b -= sum_out_b;
stack_start = sp + div - radius;
if(stack_start >= div) stack_start -= div;
stack_i = stack_start;
sum_out_r -= ((stack[stack_i] >>> 16) & 0xff);
sum_out_g -= ((stack[stack_i] >>> 8) & 0xff);
sum_out_b -= (stack[stack_i] & 0xff);
if(yp < hm)
{
src_i += w; // stride
++yp;
}
stack[stack_i] = src[src_i];
sum_in_r += ((src[src_i] >>> 16) & 0xff);
sum_in_g += ((src[src_i] >>> 8) & 0xff);
sum_in_b += (src[src_i] & 0xff);
sum_r += sum_in_r;
sum_g += sum_in_g;
sum_b += sum_in_b;
++sp;
if (sp >= div) sp = 0;
stack_i = sp;
sum_out_r += ((stack[stack_i] >>> 16) & 0xff);
sum_out_g += ((stack[stack_i] >>> 8) & 0xff);
sum_out_b += (stack[stack_i] & 0xff);
sum_in_r -= ((stack[stack_i] >>> 16) & 0xff);
sum_in_g -= ((stack[stack_i] >>> 8) & 0xff);
sum_in_b -= (stack[stack_i] & 0xff);
}
}
}
}
private static class BlurTask implements Callable<Void> {
private final int[] _src;
private final int _w;
private final int _h;
private final int _radius;
private final int _totalCores;
private final int _coreIndex;
private final int _round;
public BlurTask(int[] src, int w, int h, int radius, int totalCores, int coreIndex, int round) {
_src = src;
_w = w;
_h = h;
_radius = radius;
_totalCores = totalCores;
_coreIndex = coreIndex;
_round = round;
}
@Override public Void call() throws Exception {
blurIteration(_src, _w, _h, _radius, _totalCores, _coreIndex, _round);
return null;
}
}
}該代碼與C++的代碼同出一源。下面來(lái)簡(jiǎn)要分析一下。
public Bitmap blur(Bitmap original, float radius) {
int w = original.getWidth();
int h = original.getHeight();
int[] currentPixels = new int[w * h];
original.getPixels(currentPixels, 0, w, 0, 0, w, h);
int cores = StackBlurManager.EXECUTOR_THREADS;
ArrayList<BlurTask> horizontal = new ArrayList<BlurTask>(cores);
ArrayList<BlurTask> vertical = new ArrayList<BlurTask>(cores);
for (int i = 0; i < cores; i++) {
horizontal.add(new BlurTask(currentPixels, w, h, (int) radius, cores, i, 1));
vertical.add(new BlurTask(currentPixels, w, h, (int) radius, cores, i, 2));
}
try {
StackBlurManager.EXECUTOR.invokeAll(horizontal);
} catch (InterruptedException e) {
return null;
}
try {
StackBlurManager.EXECUTOR.invokeAll(vertical);
} catch (InterruptedException e) {
return null;
}
return Bitmap.createBitmap(currentPixels, w, h, Bitmap.Config.ARGB_8888);
}方法進(jìn)入后，首先得到圖片的像素點(diǎn)集合；而后 New 兩個(gè) List ，分別存儲(chǔ) BlurTask 。
private static class BlurTask implements Callable<Void> {
private final int[] _src;
private final int _w;
private final int _h;
private final int _radius;
private final int _totalCores;
private final int _coreIndex;
private final int _round;
public BlurTask(int[] src, int w, int h, int radius, int totalCores, int coreIndex, int round) {
_src = src;
_w = w;
_h = h;
_radius = radius;
_totalCores = totalCores;
_coreIndex = coreIndex;
_round = round;
}
@Override public Void call() throws Exception {
blurIteration(_src, _w, _h, _radius, _totalCores, _coreIndex, _round);
return null;
}
}可以看出 BlurTask 是用于進(jìn)行 線程池的回調(diào)類；其主要調(diào)用了方法 blurIteration進(jìn)行模糊。
同時(shí)給方法，傳入的參數(shù)有：
像素點(diǎn)集合
寬
高
模糊半徑
最大內(nèi)核數(shù)
當(dāng)前內(nèi)核
而后回到第一步處：
int cores = StackBlurManager.EXECUTOR_THREADS;
其實(shí)是調(diào)用的：
Runtime.getRuntime().availableProcessors();
該方法用于返回當(dāng)前虛擬機(jī)的核數(shù)；用此方法可以 最大效率的進(jìn)行多線程的分配。
而后：
for (int i = 0; i < cores; i++) {
horizontal.add(new BlurTask(currentPixels, w, h, (int) radius, cores, i, 1));
vertical.add(new BlurTask(currentPixels, w, h, (int) radius, cores, i, 2));
}可以看出往列表中加上，對(duì)應(yīng)的線程回調(diào)操作；分別是 步驟1，和步驟2
而后：
try {
StackBlurManager.EXECUTOR.invokeAll(horizontal);
} catch (InterruptedException e) {
return null;
}
try {
StackBlurManager.EXECUTOR.invokeAll(vertical);
} catch (InterruptedException e) {
return null;
}該方法中： StackBlurManager.EXECUTOR 其實(shí)是:
Executors.newFixedThreadPool(Runtime.getRuntime().availableProcessors());
可以看出其實(shí)是建立了一個(gè)線程池，線程池的運(yùn)行線程數(shù)為當(dāng)前虛擬機(jī)的核數(shù)。
然后把步驟1的集合丟進(jìn)線程池并等待執(zhí)行完成；而后丟進(jìn)步驟2.
其實(shí)從其命名就能看出：
步驟1其實(shí)是模糊水平方向
步驟2其實(shí)是模糊垂直方向
具體是不是可以看看 blurIteration 方法。
由于方法太長(zhǎng)就簡(jiǎn)化了一下：
private static void blurIteration(int[] src, int w, int h, int radius, int cores, int core, int step) {
...
if (step == 1)
{
int minY = core * h / cores;
int maxY = (core + 1) * h / cores;
for(y = minY; y < maxY; y++)
{
...
}
}
// step 2
else if (step == 2)
{
int minX = core * w / cores;
int maxX = (core + 1) * w / cores;
for(x = minX; x < maxX; x++)
<span > </span>{
<span > </span>...
<span > </span>}
}
}可以看出 分別進(jìn)行了模糊水平與垂直。
同時(shí)，在模糊時(shí)：分為了許多部分，具體取決于虛擬核數(shù)。
在這里有必要說(shuō)明一點(diǎn)就是；在模糊時(shí)只能先模糊第一步，而后才能模糊第二部。
意思就是說(shuō)第一步與第二步是不能同時(shí)進(jìn)行的；如果不贊同；可以啊把上面的兩個(gè)列表改成一個(gè)同時(shí)進(jìn)行多線程你就知道模糊的效果了。
這里截圖就不進(jìn)行截圖了，不過(guò)根據(jù)我的測(cè)試；該模糊方法在多線程下優(yōu)勢(shì)較為明顯；也就是說(shuō)手機(jī)核數(shù)越高其模糊速度越快。
如果該方法順序執(zhí)行，不使用多線程；那么其模糊所耗費(fèi)時(shí)間約比我上一章中介紹的方法多1/4的時(shí)間。
關(guān)于如何進(jìn)行圖片JNI C++\Java高斯模糊的實(shí)現(xiàn)就分享到這里了，希望以上內(nèi)容可以對(duì)大家有一定的幫助，可以學(xué)到更多知識(shí)。如果覺(jué)得文章不錯(cuò)，可以把它分享出去讓更多的人看到。
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