Develop Reference

Create Bitmap using a String

I want to create a Bitmap using the String. The problem is when I assign the Paint and String to the Canvas.
All I see is a dot/black pixel that is created is something wrong with the Configs that I am using?
Here is my code below:
private void createBitmap(){
int textSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 15, getApplicationContext().getResources().getDisplayMetrics());
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setSubpixelText(true);
paint.setStyle(Paint.Style.FILL);
paint.setTextSize(textSize);
paint.setColor(Color.BLACK);
int w = 500, h = 200;
Bitmap.Config conf = Bitmap.Config.ARGB_8888; // see other conf types
Bitmap myBitmap = Bitmap.createBitmap(w, h, conf);
Canvas myCanvas = new Canvas(myBitmap);
myCanvas.drawColor(Color.WHITE, PorterDuff.Mode.CLEAR);
myCanvas.drawText("Just a string", 0, 0, paint);
imageView = new ImageView(this);
imageView.setImageBitmap(myBitmap);
}

The y parameter is actually for the baseline of the text, so you won't really see anything with y == 0. The dot you're seeing is probably the descender of the "g" in "string".
Try changing to
myCanvas.drawText("Just a string", 0, 100, paint);
so at least you can see something.
Note: You are setting the text size based on density, but you are making the bitmap an absolute pixel size, so you are going to have to do some calculation to get the look you want.
Once you have your Paint configured, you can determine the height of the text in pixels by calling getFontMetrics() on the Paint, then looking at the FontMetrics values. ascent will be negative since it's measuring upward, so you can get a rough idea of the height by fm.descent - fm.ascent.
Here's a way to draw your text just below the top edge of the bitmap:
Paint.FontMetrics fm = paint.getFontMetrics();
int baseline = (int) - fm.ascent; // also fm.top instead of fm.ascent
myCanvas.drawText("Just a string", 0, baseline, paint);

Android Drawable Marker with Bitmap Text Overlay too Small

I am creating a Marker with text but the text is showing only 3 characters and very small and it is right of the bit map image. I want the text to go across the middle of the icon and it big font. I manually increased setFontsize to larger size did not work and also drawText width and height still did not work.
private Drawable createMarkerIcon(Drawable backgroundImage, String text,
int width, int height) {
Bitmap canvasBitmap = Bitmap.createBitmap(width, height,
Bitmap.Config.ARGB_8888); //width, height,
// Create a canvas, that will draw on to canvasBitmap.
Canvas imageCanvas = new Canvas(canvasBitmap);
// Set up the paint for use with our Canvas
Paint imagePaint = new Paint();
imagePaint.setTextAlign(Align.CENTER);
imagePaint.setTextSize(26f); // 8f
// Draw the image to our canvas
backgroundImage.draw(imageCanvas);
// Draw the text on top of our image
imageCanvas.drawText(text, width /1, height / 1, imagePaint); //2 , 2
// Combine background and text to a LayerDrawable
LayerDrawable layerDrawable = new LayerDrawable(
new Drawable[]{backgroundImage, new BitmapDrawable(canvasBitmap)});
return layerDrawable;
}
I call this function:
d=createMarkerIcon(getResources().getDrawable(R.drawable.pointer_bubble_selected), markerTxt, 100, 100); //marker_green=23x37 29, 50

Here is the solution for the text overlay bound problem. Replace one line with all this lines:
// draw text to the Canvas center
Rect bounds = new Rect();
int x = (canvasBitmap.getWidth() - bounds.width())/2;
int y = (canvasBitmap.getHeight() + bounds.height())/2;
// Draw the text on top of our image
//imageCanvas.drawText(text, width /4, height / 4, imagePaint); //OLD
imageCanvas.drawText(text, x , y, imagePaint); //NEW

Resizing a custom marker on Android maps

Im quite new to Android so forgive me if I have missed something.
I've got the following code which displays a custom marker on maps. This custom marker also has some text on it. It works well up to the point where I want to resize the marker by a certain amount when the text is longer.
The code I originally had for the custom marker was,
private Bitmap drawTextToBitmap(final int mResId, final String mText) {
Resources resources = getResources();
// Get the screen's density scale
float scale = resources.getDisplayMetrics().density;
Bitmap bitmap = BitmapFactory.decodeResource(resources, mResId);
Bitmap.Config bitmapConfig = bitmap.getConfig();
if ( bitmapConfig == null ) {
bitmapConfig = Bitmap.Config.ARGB_8888;
}
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
// Set font color
paint.setColor(Color.WHITE);
// Set font size and scale it
paint.setTextSize((int) (14 * scale));
// Set shadow width
paint.setShadowLayer(1f, 0f, 1f, Color.BLACK);
// Set anti-aliasing
paint.setAntiAlias(true);
// Make font bold
paint.setTypeface(Typeface.create(Typeface.DEFAULT, Typeface.BOLD));
Rect bounds = new Rect();
paint.getTextBounds(mText, 0, mText.length(), bounds);
int x = (bitmap.getWidth() - bounds.width())/2;
int y = ((bitmap.getHeight() + bounds.height())/2)-25;
canvas.drawText(mText, x, y, paint);
return bitmap;
}
How can I resize this bitmap and also increase the font size accordingly without loosing any resolution ? Unfortunately I cant give screenshots due to licensing/permission issues.

Found the solution which was to add the following before creating the canvas.
int newWidth = (int) (origBitmap.getWidth() * scalingFactor);
int newHeight = (int) (origBitmap.getHeight() * scalingFactor);
Bitmap bitmap = Bitmap.createScaledBitmap(origBitmap, newWidth, newHeight, true);
This will scale the bitmap accordingly. I can similarly scale the font using the same scalingFactor.

Android - Converting string to image

I need to read the text/string from database and convert them into images. I tried the following code but I am getting only blank images. Please help
public Bitmap textAsBitmap(String text, float largest, int textColor) {
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
paint.setColor(textColor);
// int width = (int) (paint.measureText(text) + 0.5f); // round
paint.setAntiAlias(true);
paint.setTypeface(Typeface.MONOSPACE);
paint.setTextSize(16);
int width = 400;
// float baseline = (int) (paint.ascent() + 0.5f) + 3f;
// int height = (int) ((baseline + paint.descent() + 0.5f) + 3);
int height = 400;
Bitmap image = Bitmap.createBitmap(width, height,
Bitmap.Config.RGB_565);
Canvas canvas = new Canvas(image);
canvas.drawText(text, 0, 5, paint);
return image;
}

I haven't tried this, but do you perhaps need to first fill your bitmap with a colour that contrasts with textColor? This would certainly seem like an important thing to do in any case -- the documentation for createBitmap() does not specify the initial content of the bitmap, so it could theoretically be anything, and may change in future versions of the system.

Center text on a bitmap

I'm trying to draw a text on the center of a bitmap however I can't do it even though I used align.center. The code is:
public Bitmap drawTextToBitmap(Context gContext, String gText) {
Resources resources = gContext.getResources();
float scale = resources.getDisplayMetrics().density;
Bitmap bitmap =
BitmapFactory.decodeResource(resources, R.drawable.blank_marker);
android.graphics.Bitmap.Config bitmapConfig =
bitmap.getConfig();
// set default bitmap config if none
if(bitmapConfig == null) {
bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
}
// resource bitmaps are imutable,
// so we need to convert it to mutable one
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
// new antialised Paint
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
// text color - #3D3D3D
paint.setColor(Color.rgb(61, 61, 61));
// text size in pixels
paint.setTextSize((int) (25 * scale));
// text shadow
paint.setShadowLayer(1f, 0f, 1f, Color.WHITE);
// draw text to the Canvas center
Rect bounds = new Rect();
paint.setTextAlign(Align.CENTER);
paint.getTextBounds(gText, 0, gText.length(), bounds);
int x = (bitmap.getWidth() - bounds.width())/2;
int y = (bitmap.getHeight() + bounds.height())/2;
canvas.drawText(gText, x * scale, y * scale, paint);
return bitmap;
}
What am I doing wrong?

It's a lot more straightforward than you think.
Draw the text at half the Bitmap's width and height (center point) in combination with Paint.setTextAlign(Align.CENTER).
The alignment property will take care of the rest.

I guess none of the answers given above are good enough so I post my answer. Try it out guys, it will work on all devices and is not complex at all:
String text = "Text"; //your string
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(activity.getResources().getColor(R.color.white));
paint.setTextSize(30);
// draw text to the Canvas center
Rect boundsText = new Rect();
paint.getTextBounds(text, 0, text.length(), boundsText);
int x = (bitmap.getWidth() - boundsText.width()) / 2;
int y = (bitmap.getHeight() + boundsText.height()) / 2;
canvas.drawText(text, x, y, paint);

Where is the text drawing? The issue might be since you changed the text align to Align.CENTER. Your code calculating x and y assumes the text rendering is using Align.LEFT, I believe.
Either use setTextAlign(Align.CENTER) and render at the actual bitmap center, or use setTextAlign(Align.LEFT) and use the current x and y calculations you are using.