ios - iPhone : How to change color of particular pixel of a UIImage? -

i have uiimage, want change colour of particular pixel, 224 x 200th pixel. how can this? possible do? in advance.

after searching lot complete day got exact solution, though found many none of them worked. here have got, works flawlessly -:

// method creates image changing individual pixels of image. color of pixel has been taken array of colours('avgrgbsofpixel') -(void)createtexture{  self.sampleimage = [[uiimageview alloc]initwithimage:[uiimage imagenamed:@"whitebg.jpg"]]; cgrect imagerect = cgrectmake(0, 0, self.sampleimage.image.size.width, self.sampleimage.image.size.height);  uigraphicsbeginimagecontext(sampleimage.image.size); cgcontextref context = uigraphicsgetcurrentcontext();  //save current status of graphics context cgcontextsavegstate(context); cgcontextdrawimage(context, imagerect, sampleimage.image.cgimage); //    , draw point on wherever want this:  //    cgcontextfillrect(context, cgrectmake(x,y,1,1)); //fix error according @gsempe's comment int pixelcount =0; for(int = 0 ; i<sampleimage.image.size.width ; i++){     for(int j = 0 ; j<sampleimage.image.size.height ; j++){         pixelcount++;         int index = pixelcount/pixelcountforcalculatingavgcolor;         //            nslog(@"index : %d", index);         if(index >= [avgrgbsofpixel count]){             index = [avgrgbsofpixel count] -1;             nslog(@"bad index");         }         //            if(pixelcount >9999){         //                pixelcount = 9999;         //                nslog(@"bad index");         //            }         uicolor *color = [avgrgbsofpixel objectatindex:index];         float red ,green, blue ,alpha ;         [color getred:&red green:&green blue:&blue alpha:&alpha];         cgcontextsetrgbfillcolor(context, red , green, blue , 1);         cgcontextfillrect(context, cgrectmake(i,j,1,1));     } }  //    save uiimage again:  cgcontextrestoregstate(context); uiimage *img = uigraphicsgetimagefromcurrentimagecontext(); [self.iv setimage:img]; 

}