Develop Reference

How to draw a text at the corner of a bitmap android

I have a bitmap and I am trying to draw a text over the bitmap at the top right corner. But at the first place I am not able to draw any text over it. I am converting a layout to bitmap and then trying to draw text over it. But its not working out. Here is my code:
private Bitmap viewToBitmap(LinearLayout layout) {
Bitmap bitmap = Bitmap.createBitmap(layout.getWidth(), layout.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
layout.draw(canvas);
canvas=new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setAntiAlias(true);
paint.setTextSize(14.f);
paint.setTextAlign(Paint.Align.CENTER);
canvas.drawText("Hello Android!", 0, 0, paint);
return bitmap;
}

Please pay much attention to the text position & alignment.
private Bitmap viewToBitmap(View view)
{
Bitmap result = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(result);
view.draw(canvas);
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setAntiAlias(true);
paint.setTextSize(14);
paint.setTextAlign(Paint.Align.RIGHT);
canvas.drawText("Hello Android!", view.getWidth(), 14, paint); // draw watermark at top right corner
return result;
}

Masked bitmap on canvas with transparent activity

I implemented custom ShowCase for activity
I am trying to draw on canvas mask:
http://i.stack.imgur.com/u23kQ.png
Following this code:
mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
// draw solid background
mCanvas.drawColor(mMaskColour);
// Prepare eraser Paint if needed
if (mEraser == null) {
mEraser = new Paint();
mEraser.setColor(0xFFFFFFFF);
mEraser.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
mEraser.setFlags(Paint.ANTI_ALIAS_FLAG);
}
// draw (erase) shape
// mShape.draw(mCanvas, mEraser, mXPosition, mYPosition, mShapePadding);
mCanvas.drawBitmap(cBitmap,mXPosition,mYPosition,mEraser);
// Draw background
canvas.drawBitmap(mBitmap, 0, 0, null);
But it appears like this:
http://i.stack.imgur.com/MhcOt.png

I solve this
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
mCanvas.drawBitmap(cBitmap,mXPosition,mYPosition,paint);
// mShape.draw(canvas, mEraser, mXPosition, mYPosition, mShapePadding);
// Draw the bitmap on our views canvas.
canvas.drawBitmap(mBitmap, 0, 0, null);

Draw text with a shape mask?

I am drawing text on a canvas. I would like to draw a solid circle of color over the text, and only have the circle be painted where it intersects the text. Example:
and what I want to do:
I'm not sure if this is possible, my draw code is simply:
public void onDraw(Canvas canvas) {
canvas.drawText("Hello", x, y, paint);
paint.setColor(orange);
canvas.drawOval(...);
}
I suppose I would need to apply some masking, but not sure how to get started.

follow this tutorial from a googler...
android-shaders-filters
BitmapShader may help you

You can use PorterDuffXfermode in Android to achieve this.
If you use below code it will work fine:
Bitmap original = Bitmap.createBitmap(canvas.getWidth(), canvas.getHeight(),
Bitmap.Config.ARGB_8888); // Created from Canvas
Bitmap mask =
Bitmap.createBitmap(getContext().getResources(),R.drawable.mask_image);
Bitmap result = Bitmap.createBitmap(mask.getWidth(), mask.getHeight(),
Config.ARGB_8888);
Canvas tempCanvas = new Canvas(result);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
tempCanvas.drawBitmap(original, 0, 0, null);
paint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
tempCanvas.drawBitmap(mask, 0, 0, paint);
paint.setXfermode(null);
canvas.drawBitmap(result, 0, 0, new Paint());
What does PorterDuff.Mode mean in android graphics.What does it do?

Android : Constructing bitmap from RECT

Can we construct a bitmap from a rect.
I draw a bitmap in a rect and want strokes drawn on the bitmap image become part of the image.
I am wondering if I can construct a bitmap from a Rect so the new bitmap has the old image and the strokes as a single image.
Thank You

You can always take a canvas to help you create an already decoded bitmap the way you want:
Bitmap originalBmp = null;//Here goes original Bitmap...
ImageView img = null;//Any imageview holder you are using...
Bitmap modifiedBmp = Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888);//Configure with your proper size and color
Canvas canvas = new Canvas(modifiedBmp);
//At this point the modified bitmap has the original one, starting from here, you can add any overlay you want...
canvas.drawBitmap(originalBmp, 0, 0, new Paint());
//And do all the other modifications you want here...
canvas.drawLines(new float[]{}, null);
canvas.drawCircle(x, y, radius, null);
//At this point the modified bitmap will have anything you added
img.setImageBitmap(modifiedBmp);
// IF YOU ARE OVERRIDING ONDRAW METHOD
public void onDraw(Canvas canvas){
//Here DO your DRAW BITMAP NOTE: paint must be already created...
canvas.drawBitmap(bt, 0, 0, paint);
paint.setColor(Color.BLACK);
paint.setStrokeWidth(3);
canvas.drawRect(30, 30, 80, 80, paint);
super.onDraw(canvas);
}
Regards!

Yes you can , Using canvas you can draw something on your old bimtap .
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
// do some canvas drawing
canvas.drawBitmap(bitmap, rect, rect, paint);

Canvas object as thumb in SeekBar, Test align. Android

I have a problem with set up the right position of the text as a paint in canvas object,
which I use as thumb in customise SeekBar.
public BitmapDrawable writeOnDrawable(int drawableId, String text)
{
Bitmap bm = BitmapFactory.decodeResource(getResources(),drawableId).copy(Bitmap.Config.ARGB_8888, true);
bm.setDensity(165);
Paint paint = new Paint();
paint.setStyle(Style.FILL);
paint.setColor(Color.WHITE);
paint.setTextSize(size);
paint.setTypeface(my.b1);
paint.setTextAlign(Paint.Align.CENTER);
Canvas canvas = new Canvas(bm);
canvas.setDensity(165);
canvas.drawText(text, 0, bm.getHeight()/2, paint);
return new BitmapDrawable(bm);
}
There is a circle with current progress. So the text is
dynamic cause can be from 2 characters ("0-9%") to
4 characters ("100%"). Also the problem is not only with position,
but also with the size of the text.