Develop Reference

canvas text looks blurry on images in android

When drawing the text though, it gets blurred and not that crisp like when using below code. The only code I've used for the text painting on image can some one help me to solve this issue
code
public static Bitmap drawMultilineTextToBitmap(Context gContext, Bitmap bitmap, String gText) {
// prepare canvas
Resources resources = gContext.getResources();
float scale = resources.getDisplayMetrics().density;
//Bitmap bitmap = BitmapFactory.decodeResource(resources, gResId);
android.graphics.Bitmap.Config bitmapConfig = bitmap.getConfig();
// set default bitmap config if none
if (bitmapConfig == null) {
bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
}
// so we need to convert it to mutable one
bitmap = bitmap.copy(bitmapConfig, true);
Canvas canvas = new Canvas(bitmap);
TextPaint paint = new TextPaint(Paint.LINEAR_TEXT_FLAG|Paint.ANTI_ALIAS_FLAG);
paint.setStyle(Paint.Style.FILL);
paint.setAntiAlias(true);
paint.setColor(Color.rgb(0, 0, 0));
paint.setFakeBoldText(true);
paint.setTextSize(10);
int textWidth = canvas.getWidth() - (int) (16 * scale);
// init StaticLayout for text
StaticLayout textLayout = new StaticLayout(gText, paint,
canvas.getWidth(), Layout.Alignment.ALIGN_NORMAL, 1.0f, 0.0f,
false);
// get height of multiline text
int textHeight = textLayout.getHeight();
// get position of text's top left corner
float x = (bitmap.getWidth() - textWidth);
float y = (bitmap.getHeight() - textHeight);
// draw text to the Canvas Left
canvas.save();
//canvas.translate(x, y);
canvas.translate((canvas.getWidth() / 2) - (textLayout.getWidth() / 2), y);
textLayout.draw(canvas);
canvas.restore();
return bitmap;
}
image

I guess here:
paint.setAntiAlias(true);
should be false. And two more methods which may relate to this issue:
paint.setAntiAlias(false);
paint.setFilterBitmap(false);
paint.setDither(true);

How to convert the text to bitmap in Android

please help me to draw a text with rounded rectangle as background. I have to draw many texts on a canvas and the text has rounded background. SO what I am trying is to write a function "createTextBitmap" which return a bitmap image so that we can draw image(which return by the function) on a main canvas.
the 'createTextBitmap'function can return a created bitmap, the bitmap image is the one,which contains the text with rounded edge background...
i have tried one, which gives below.
private Bitmap ProcessingBitmap(String text,Paint paint, boolean lastPoint){
Bitmap bm1 = null;
Bitmap newBitmap = null;
Rect bounds = new Rect();
paint.getTextBounds(text, 0, text.length(), bounds);
float width = bounds.width();
float height =bounds.height();
float radius;
if (width > height){
radius = height/4;
}else{
radius = width/4;
}
Paint paint1 = new Paint();
paint1.setColor(Color.GREEN);
paint1.setStrokeWidth(5);
paint1.setStyle(Paint.Style.FILL);
float center_x, center_y;
center_x = width/4;
center_y = height/4;
final RectF rect = new RectF();
rect.set(center_x - radius,
center_y - radius,
center_x + radius,
center_y + radius);
Canvas canvas2 = new Canvas();
canvas2.drawRoundRect(rect, 0, 0, paint);
canvas2.drawText(text, 0, 0, paint);
return newBitmap;
}
and my question is How can we convert this canvas2 to a bitmap image? and image has the size of text bounds,
which look like

to convert your canvas into bitmap please do the following :
public Bitmap convertCanvasToBitmap(int width , int height) {
Bitmap drawnBitmap = null;
try {
drawnBitmap = Bitmap.createBitmap(width, height, Config.ARGB_8888);
Canvas canvas = new Canvas(drawnBitmap);
// now draw anything you want to the canvas
} catch (Exception e) {
e.printStackTrace();
}
return drawnBitmap;
}
so the idea is just pass the bitmap to the canvas , draw with the canvas it will be drawn into your bitmap .
and please refer to this answer here to see how to deal with the text size in the bitmap .
and please give me some feedback
Hope that helps .

you can create a bitmap, then call draw on that bitmap, something like this:
newBitmap = Bitmap.createBitmap(rect.width, rect.height, Bitmap.Config.ARGB_8888);
Canvas canvas2 = new Canvas(newBitmap);

How to write text more than 10 letters using Canvas and paint on map?

Marking few markers and adding names using Canvas and Paint on map. But am able to see the text only 9 characters rest are hiding (not visible). How to do it?
private Bitmap drawTitleOnMarkerIcon(MarkingInfo markingInfo) {
Bitmap bm = BitmapFactory.decodeResource(getResources(), AddLocationTypeIcon.getIcon(markingInfo.getType())).copy(
Bitmap.Config.ARGB_8888, true);
Canvas canvas = new Canvas(bm);
Paint paint = new Paint();
paint.setColor(Color.BLUE);
paint.setAntiAlias(true);
paint.setFakeBoldText(true);
paint.setTextSize(16);
paint.setTextAlign(Align.LEFT);
canvas.drawText(markingInfo.getName(), 0, 60, paint);
BitmapDrawable draw = new BitmapDrawable(getResources(), bm);
return draw.getBitmap();
}
I should able to see complete text, When I have more than 15 character just I need to wrap it to next line. search many sites and posted query previously but I got no solution. please do help to achieve this task

private Bitmap textAsBitmap(String text, float textSize, int textColor) {
Paint paint = new Paint();
paint.setTextSize(textSize);
paint.setColor(textColor);
paint.setFakeBoldText(true);
paint.setTextAlign(Paint.Align.LEFT);
int width = (int) (paint.measureText(text) + 0.5f); // round
float baseline = (int) (-paint.ascent() + 0.5f); // ascent()is negative
int height = (int) (baseline + paint.descent() + 0.5f);
Bitmap image = Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(image);
canvas.drawText(text, 0, baseline, paint);
return image;
}
MarkerOptions().title(Name()).icon(BitmapDescriptorFactory.fromBitmap(textAsBitmap));

Draw a circle on bitmap

I have searched for many answers here for drawing a circle on bitmap using canvas. However, I got some error in the code and the application stopped without any exception.
Can anyone give me some help? It works fine with I create a blank bitmap and draw a circle on it.
Any help will be appreciated!
Bitmap bmp = BitmapFactory.decodeResource(getResources(), R.drawable.main);
Paint paint = new Paint();
//paint.setAntiAlias(true);
paint.setColor(Color.BLUE);
Canvas canvas = new Canvas(bmp);
canvas.drawCircle(50, 50, 10, paint);
ImageView imageView = (ImageView)findViewById(R.id.imageView1);
//imageView.setAdjustViewBounds(true);
imageView.setImageBitmap(bmp);

Read somewhere that Resource bitmaps are immutable. Try...
bmp = bmp.copy(bmp.getConfig(), true);

This will draw a circle for you for given height
private RectF outerCircle;
diameter =400;
int left = (width - diameter) / 2;
int top = (height - diameter) / 2;
int bottom = top + diameter;
int right = left + diameter;
outerCircle = new RectF(left, top, right, bottom);

Circle drawn on canvas doesn't match the screen

I want to draw circle in center of screen, but I'm getting something like this:
I'm using this code to draw this circle.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Display display = getWindowManager().getDefaultDisplay();
int width = display.getWidth();
int height = display.getHeight();
Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_4444);
Canvas c = new Canvas(bmp);
RectF rect = new RectF(0,0,width,width);
drawCircle(rect, c, width, height);
ImageView img = (ImageView) findViewById(R.id.imageView1);
img.setImageBitmap(bmp);
img.setScaleType(ScaleType.FIT_CENTER);
}
private void drawCircle(RectF rect, Canvas c, int width, int height) {
Paint paint = new Paint();
paint.setARGB(255, 255 , 10, 21);
paint.setStrokeWidth(10);
paint.setAntiAlias(true);
paint.setStrokeCap(Paint.Cap.BUTT);
paint.setStyle(Paint.Style.STROKE);
int radius;
if(width < height)
radius = width/2;
else
radius = height/2;
c.drawCircle(width/2, height/2, radius, paint);
}
I don't understand why it's cut at sides even though I use size of screen to draw it, so it should perfectly fit it.

You didn't account for the thickness of the line (strokeWidth). You drew a circle assuming it had 0 thickness, so the "actual" circle IS touching the edges of the screen, but since you used a thick paintbrush, some of the paint leaked past the edge.

you should decrease the thickness/2.
private void drawCircle(RectF rect, Canvas c, int width, int height) {
Paint paint = new Paint();
paint.setARGB(255, 255 , 10, 21);
paint.setStrokeWidth(10);
paint.setAntiAlias(true);
paint.setStrokeCap(Paint.Cap.BUTT);
paint.setStyle(Paint.Style.STROKE);
int radius;
if(width < height)
radius = width/2;
else
radius = height/2;
//this is the new line:
radius-= 5;
c.drawCircle(width/2, height/2, radius, paint);
}

Account for the StrokeWidth in the radius:
// Substract stroke width.
radius -= paint.getStrokeWidth() / 2;
c.drawCircle(width/2, height/2, radius, paint);