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POimplement water color effect on image using JNI
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  1. POimplement water color effect on image using JNI
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    copied!<p>i implement some code for water color effect on image in android but it was to slow(it's take more then 2 minute) now i try to implement this in JNI for batter speed , hear is my java code for </p> <p>the inPixels is pixel of Bitmap .</p> <pre><code> protected int[] filterPixels( int width, int height, int[] inPixels ) { int levels = 256; int index = 0; int[] rHistogram = new int[levels]; int[] gHistogram = new int[levels]; int[] bHistogram = new int[levels]; int[] rTotal = new int[levels]; int[] gTotal = new int[levels]; int[] bTotal = new int[levels]; int[] outPixels = new int[width * height]; for (int y = 0; y &lt; height; y++) { for (int x = 0; x &lt; width; x++) { for (int i = 0; i &lt; levels; i++) rHistogram[i] = gHistogram[i] = bHistogram[i] = rTotal[i] = gTotal[i] = bTotal[i] = 0; for (int row = -range; row &lt;= range; row++) { int iy = y+row; int ioffset; if (0 &lt;= iy &amp;&amp; iy &lt; height) { ioffset = iy*width; for (int col = -range; col &lt;= range; col++) { int ix = x+col; if (0 &lt;= ix &amp;&amp; ix &lt; width) { int rgb = inPixels[ioffset+ix]; int r = (rgb &gt;&gt; 16) &amp; 0xff; int g = (rgb &gt;&gt; 8) &amp; 0xff; int b = rgb &amp; 0xff; int ri = r*levels/256; int gi = g*levels/256; int bi = b*levels/256; rTotal[ri] += r; gTotal[gi] += g; bTotal[bi] += b; rHistogram[ri]++; gHistogram[gi]++; bHistogram[bi]++; } } } } int r = 0, g = 0, b = 0; for (int i = 1; i &lt; levels; i++) { if (rHistogram[i] &gt; rHistogram[r]) r = i; if (gHistogram[i] &gt; gHistogram[g]) g = i; if (bHistogram[i] &gt; bHistogram[b]) b = i; } r = rTotal[r] / rHistogram[r]; g = gTotal[g] / gHistogram[g]; b = bTotal[b] / bHistogram[b]; outPixels[index] = (inPixels[index] &amp; 0xff000000) | ( r &lt;&lt; 16 ) | ( g &lt;&lt; 8 ) | b; index++; } } return outPixels; } </code></pre> <p>**OUTPUT image ** <img src="https://i.stack.imgur.com/arZP0.png" alt="enter image description here"></p> <p>and i try to convert this <code>java</code> code to <code>c</code> code but i don't what is the wrong , hear the code for <code>C</code> </p> <pre><code> void filterPixels( int width, int height, int inPixels[] ) { int levels = 256; int index = 0; int rHistogram [levels]; int gHistogram [levels]; int bHistogram [levels]; int rTotal [levels]; int gTotal [levels]; int bTotal [levels]; int outPixels [width * height]; //Loop Variables int y ; int x ; int i ; int row ; int col ; int j ; int range = 5 ; for ( y = 0; y &lt; height; y++) { for ( x = 0; x &lt; width; x++) { for ( i = 0; i &lt; levels; i++) rHistogram[i] = gHistogram[i] = bHistogram[i] = rTotal[i] = gTotal[i] = bTotal[i] = 0; for ( row = -range; row &lt;= range; row++) { int iy = y+row; int ioffset; if (0 &lt;= iy &amp;&amp; iy &lt; height) { ioffset = iy*width; for ( col = -range; col &lt;= range; col++) { int ix = x+col; if (0 &lt;= ix &amp;&amp; ix &lt; width) { int rgb = inPixels[ioffset+ix]; int r = (rgb &gt;&gt; 16) &amp; 0xff; int g = (rgb &gt;&gt; 8) &amp; 0xff; int b = rgb &amp; 0xff; int ri = r*levels/256; int gi = g*levels/256; int bi = b*levels/256; rTotal[ri] += r; gTotal[gi] += g; bTotal[bi] += b; rHistogram[ri]++; gHistogram[gi]++; bHistogram[bi]++; } } } } int r = 0, g = 0, b = 0; for ( j = 1; j &lt; levels; j++) { if (rHistogram[j] &gt; rHistogram[r]) r = j; if (gHistogram[j] &gt; gHistogram[g]) g = j; if (bHistogram[j] &gt; bHistogram[b]) b = j; } r = rTotal[r] / rHistogram[r]; g = gTotal[g] / gHistogram[g]; b = bTotal[b] / bHistogram[b]; outPixels[index] = (inPixels[index] &amp; 0xff000000) | ( r &lt;&lt; 16 ) | ( g &lt;&lt; 8 ) | b; index++; } } } </code></pre> <p>i check the pixel value of <code>java</code> code and <code>c</code> code both are same(for same image)</p> <p>code for call native function from my android activity .</p> <pre><code>int[] pix = new int[oraginal.getWidth() * oraginal.getHeight()]; Bitmap bitmap = oraginal.copy(oraginal.getConfig(), true); bitmap.getPixels(pix, 0, bitmap.getWidth(), 0, 0,bitmap.getWidth(), bitmap.getHeight()); filterPixelsJNI(bitmap.getWidth(), bitmap.getHeight(), pix); bitmap.setPixels(pix, 0, bitmap.getWidth(), 0, 0,bitmap.getWidth(), bitmap.getHeight()); myView.setImageBitmap(bitmap); </code></pre> <p>this is my first try for JNI so plz help me in this . </p> <p><strong>UPDATE</strong></p> <pre><code>public native void filterPixelsJNI( int width, int height, int inPixels[] ); </code></pre> <p><strong>JNI</strong> </p> <pre><code> JNIEXPORT void JNICALL Java_com_testndk_HelloWorldActivity_filterPixelsJNI (JNIEnv * env, jobject obj , jint width,jint height,jint inPixels[]){ filterPixels( width, height, inPixels); } </code></pre> <p>filterPixels method witch is call from c code . </p>
 

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