How can I replace the black color in a bitmap with red (or any other color) programmatically in Android (ignoring transparency)? I can replace the white color in the bitmap with a color already but it somehow does not work with black.
Thanks for help.
Get all the pixels in the bitmap using this:
int [] allpixels = new int [myBitmap.getHeight() * myBitmap.getWidth()];
myBitmap.getPixels(allpixels, 0, myBitmap.getWidth(), 0, 0, myBitmap.getWidth(), myBitmap.getHeight());
for(int i = 0; i < allpixels.length; i++)
{
if(allpixels[i] == Color.BLACK)
{
allpixels[i] = Color.RED;
}
}
myBitmap.setPixels(allpixels,0,myBitmap.getWidth(),0, 0, myBitmap.getWidth(),myBitmap.getHeight());
This works for me
public Bitmap replaceColor(Bitmap src,int fromColor, int targetColor) {
if(src == null) {
return null;
}
// Source image size
int width = src.getWidth();
int height = src.getHeight();
int[] pixels = new int[width * height];
//get pixels
src.getPixels(pixels, 0, width, 0, 0, width, height);
for(int x = 0; x < pixels.length; ++x) {
pixels[x] = (pixels[x] == fromColor) ? targetColor : pixels[x];
}
// create result bitmap output
Bitmap result = Bitmap.createBitmap(width, height, src.getConfig());
//set pixels
result.setPixels(pixels, 0, width, 0, 0, width, height);
return result;
}
Now set your bit map
replaceColor(bitmapImg,Color.BLACK,Color.GRAY )
For better view please check this Link
#nids : Have you tried replacing your Color to Color.TRANSPARENT ? That should work...
Related
I have a drawable that represents a white circle with anti-aliasing that needs to be coloured in runtime.
Here's a scaled image of it:
As you can see, there are few semi-transparent pixels.
If I try to color them the fast way (which takes roughly 6-9 ms for 192x192 px drawable), I will have troubles with semi-transparent.
public static void changeBitmapColor(#NonNull Bitmap src, #ColorInt int newColor) {
Paint paint = new Paint();
ColorFilter filter = new PorterDuffColorFilter(newColor, PorterDuff.Mode.SRC_IN);
paint.setColorFilter(filter);
Canvas canvas = new Canvas(src);
canvas.drawBitmap(src, 0, 0, paint);
}
Here's the drawable after being coloured by setting ColorFilter:
If I do it using brute-force algorithm, it takes roughly 100ms to go over all pixels and apply alpha parameter to a new color:
public static void changeBitmapColor2(#NonNull Bitmap src, #ColorInt int newColor) {
int w = src.getWidth();
int h = src.getHeight();
for (int x = 0; x < w; x++) {
for (int y = 0; y < h; y++) {
int color = src.getPixel(x, y);
int alpha = color >>> 24;
if (alpha == 0) {
continue;
}
color = (newColor & 0x00ffffff) | (alpha << 24);
src.setPixel(x, y, color);
}
}
}
The resulting image of 2nd algorithm:
Is there anything I could do with 1st algorithm that it will result in a better quality colouring without sacrificing the performance?
Turns out, the 2nd algorithm had the right idea, but poor implementation. The key was to batch pixel retrieval and set, i.e. using pixel array:
public static void changeBitmapColor2(#NonNull Bitmap src, #ColorInt int newColor) {
int width = src.getWidth();
int height = src.getHeight();
int[] pixels = new int[height * width];
src.getPixels(pixels, 0, width, 0, 0, width, height);
int newColorNoAlpha = newColor & 0x00ffffff;
for (int i = 0; i < width; i++) {
for (int j = 0; j < height; j++) {
int currentPixel = i * width + j;
int color = pixels[currentPixel];
int alpha = color >>> 24;
if (alpha == 0) {
continue;
}
pixels[currentPixel] = newColorNoAlpha | (alpha << 24);
}
}
src.setPixels(pixels, 0, width, 0, 0, width, height);
}
This batching has reduced time to change color of 200x200 image from 100-120ms to 1-4 ms :)
Anyone know how to add subtle noise to grayscale image?
I have a grayscale image that I want to add some subtle black and white noise to. Anyone know how to do this?
I'm currently using this method, but this is just generating random colors and swapping existing pixels with those colors. How can I add some subtle black and white noise to only SOME pixels on a bitmap?
public static Bitmap applyFleaEffect(Bitmap source) {
// get source image size
int width = source.getWidth();
int height = source.getHeight();
int[] pixels = new int[width * height];
// get pixel array from source
source.getPixels(pixels, 0, width, 0, 0, width, height);
// create a random object
Random random = new Random();
int index = 0;
// iteration through pixels
for(int y = 0; y < height; ++y) {
for(int x = 0; x < width; ++x) {
// get current index in 2D-matrix
index = y * width + x;
// get random color
int randColor = Color.rgb(random.nextInt(255),
random.nextInt(255), random.nextInt(255));
// OR
pixels[index] |= randColor;
}
}
// output bitmap
Bitmap bmOut = Bitmap.createBitmap(width, height, source.getConfig());
bmOut.setPixels(pixels, 0, width, 0, 0, width, height);
return bmOut;
}
}
UPDATE: Adding complete code to show grayscale step, and attempted noise step
//First, apply greyscale to make Image black and white
Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, mBitmap.getConfig());
Canvas c = new Canvas(bmpGrayscale);
Paint paint = new Paint();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
paint.setColorFilter(f);
//Apply noise after grayscale
int[] pixels = new int[width * height];
bmpGrayscale.getPixels(pixels, 0, width, 0, 0, width, height);
// a random object
Random random = new Random();
int index = 0;
// Note: Declare the c and randColor variables outside of the for loops
int co = 0;
int randColor = 0;
// iteration through pixels
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
if (random.nextInt(101) < percentNoise) {
// Skip this iteration a certain percentage of the time
continue;
}
// get current index in 2D-matrix
index = y * width + x;
co = random.nextInt(255);
randColor = Color.rgb(co, co, co);
pixels[index] |= randColor;
}
}
// output bitmap
mBitmap = Bitmap.createBitmap(width, height, bmpGrayscale.getConfig());
mBitmap.setPixels(pixels, 0, width, 0, 0, width, height);
c.drawBitmap(mBitmap, 0, 0, paint);
return bmpGrayscale;
}
First, randColor is not likely to be a gray-scale color with your code. To generate a random, gray-scale color:
int c = random.nextInt(255);
int randColor = Color.rgb(c, c, c);
With that in mind, here is how I would re-write your code (note: adjust the percentNoise parameter to your liking):
public static Bitmap applyFleaEffect(Bitmap source, int percentNoise) {
// get source image size
int width = source.getWidth();
int height = source.getHeight();
int[] pixels = new int[width * height];
// get pixel array from source
source.getPixels(pixels, 0, width, 0, 0, width, height);
// create a random object
Random random = new Random();
int index = 0;
// Note: Declare the c and randColor variables outside of the for loops
int c = 0;
int randColor = 0;
// iterate through pixels
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width; ++x) {
if (random.nextInt(101) < percentNoise) {
// Skip this iteration a certain percentage of the time
continue;
}
// get current index in 2D-matrix
index = y * width + x;
// get random color
c = random.nextInt(255);
randColor = Color.rgb(c, c, c);
pixels[index] |= randColor;
}
}
Bitmap bmOut = Bitmap.createBitmap(width, height, source.getConfig());
bmOut.setPixels(pixels, 0, width, 0, 0, width, height);
return bmOut;
}
I have created a diagonal white line on a custom view from one corner of screen to another corner using this-
canvas.drawLine(0, 0, MainActivity.width+10, MainActivity.height, paint);
I know how to getPixels and setPixels on a Bitmap, like this-
public Bitmap generateAlphaMask(Bitmap bmpTop,Bitmap bmpBottom) {
int width = bmpTop.getWidth();
int height = bmpTop.getHeight();
boolean[][] res = new boolean[width][height];
int[] colors = new int[width * height];
bmpTop.getPixels(colors, 0, width, 0, 0, width, height);
for (int x = 0; x < width; ++x) {
for (int y = 0; y < height; ++y) {
int cell = y * width + x;
int redVal = Color.red(colors[cell]);
int greenVal = Color.green(colors[cell]);
int blueVal = Color.blue(colors[cell]);
int alpha = Color.alpha(colors[cell]);
res[x][y] = alpha == ALPHA_THRESHOLD;
if (res[x][y]) {
bmpBottom.setPixel(x, y, Color.TRANSPARENT);
}
}
}
return bmpBottom;
}
But I want to store Pixel Positions from canvas where the pixel is "not white".
Help me regarding this.
I am writing some function to add noise effect on bitmap. I found similar question: Add noise effect to a drawing
Bitmap outputBitmap = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
BitmapShader shader = new BitmapShader (bitmap, TileMode.REPEAT, TileMode.REPEAT);
Paint paint = new Paint();
paint.setShader(shader);
Canvas c = new Canvas(outputBitmap);
c.drawBitmap(bitmap, 0, 0, paint);
How should i add color filter to get such a result? Could you provide somple code?
i suggested that use this code.
public static final int COLOR_MIN = 0x00;
public static final int COLOR_MAX = 0xFF;
public static Bitmap applyFleaEffect(Bitmap source) {
// get image size
int width = source.getWidth();
int height = source.getHeight();
int[] pixels = new int[width * height];
// get pixel array from source
source.getPixels(pixels, 0, width, 0, 0, width, height);
// a random object
Random random = new Random();
int index = 0;
// iteration through pixels
for(int y = 0; y < height; ++y) {
for(int x = 0; x < width; ++x) {
// get current index in 2D-matrix
index = y * width + x;
// get random color
int randColor = Color.rgb(random.nextInt(COLOR_MAX),
random.nextInt(COLOR_MAX), random.nextInt(COLOR_MAX));
// OR
pixels[index] |= randColor;
}
}
// output bitmap
Bitmap bmOut = Bitmap.createBitmap(width, height, source.getConfig());
bmOut.setPixels(pixels, 0, width, 0, 0, width, height);
return bmOut;
}
welcome.
How can i to get color/alpha of pixel from Sprite in andengine without creating any additional Bitmap?
I solved this problem by using this function
private void loadObjectsMask()
{
InputStream in = null;
Bitmap maskForObjects=null;
try {
final BitmapFactory.Options decodeOptions = new BitmapFactory.Options();
decodeOptions.inPreferredConfig = Bitmap.Config.ARGB_4444;
in = GameActivity.this.getAssets().open("images/" + BACKGROUND_PATH + getObjectImgFile());
maskForObjects = BitmapFactory.decodeStream(in, null, decodeOptions);
} catch (final IOException e) {
} finally {
StreamUtils.close(in);
}
if (maskForObjects != null)
{
objectsMask=new byte[maskForObjects.getWidth()][maskForObjects.getHeight()];
for(int pw=0;pw<maskForObjects.getWidth();++pw)
{
for(int ph=0;ph<maskForObjects.getHeight();++ph)
{
objectsMask[pw][ph]=(byte)(Color.alpha(maskForObjects.getPixel(pw, ph))==0?0:1);
}
}
maskForObjects.recycle();
System.out.printf("Bitmap size %d %d\n", maskForObjects.getWidth(),maskForObjects.getHeight());
}
else System.out.printf("Bitmap size error\n");
}
have a look this method, this method are used to effect on each pix
public Bitmap invert(Bitmap src) {
// image size
int width = src.getWidth();
int height = src.getHeight();
// create output bitmap
Bitmap bmOut = Bitmap.createBitmap(width, height, src.getConfig());
// color information
int A, R, G, B;
int pixel;
// scan through all pixels
for(int x = 0; x < width; ++x) {
for(int y = 0; y < height; ++y) {
// get pixel color
pixel = src.getPixel(x, y);
// get color on each channel
A = Color.alpha(pixel);
R = Color.red(pixel);
G = Color.green(pixel);
B = Color.blue(pixel);
// set new pixel color to output image
bmOut.setPixel(x, y, Color.argb(A, 255-R, 255-G, 255-B));
}
}
// return final image
return bmOut;
}
To convert Gray Scale
public static Bitmap toGrayscale(Bitmap bmpOriginal)
{
int width, height;
height = bmpOriginal.getHeight();
width = bmpOriginal.getWidth();
Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
Canvas c = new Canvas(bmpGrayscale);
Paint paint = new Paint();
ColorMatrix cm = new ColorMatrix();
cm.setSaturation(0);
ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
paint.setColorFilter(f);
c.drawBitmap(bmpOriginal, 0, 0, paint);
return bmpGrayscale;
}