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);

Google Maps custom Marker with Business Logo

for an Android App I need a custom marker for my google maps activity. The standard option do not help me. what is the best way to achieve the right icon with a businesslogo that can be set for each marker?
UPDATE:
Sorry, either I wasn't clear enough or I don't see it. I can't find a lot helpful things in the docs or the hints you gave me. Now I constructed a default marker:
and I have lots of profile pics or logos wich need to be placed within the marker at runtime depending on certain conditions e.g.:

There is a documentation about adding custom markers on a position.
private static final LatLng MELBOURNE = new LatLng(-37.813, 144.962);
private Marker melbourne = mMap.addMarker(new MarkerOptions()
.position(MELBOURNE)
.title("Melbourne")
.snippet("Population: 4,137,400")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.arrow)));

for making custom view you have to use MarkerDemoActivity class to use a custom marker.if you are using google map Api V2.0.
and other solution to make custom view for marker.
Add this code to add marker of map:
Marker myLocMarker = map.addMarker(new MarkerOptions()
.position(myLocation)
.icon(BitmapDescriptorFactory.fromBitmap(writeTextOnDrawable(R.drawable.bluebox, "your text goes here"))));
the writeTextOnDrawable() Method:
private Bitmap writeTextOnDrawable(int drawableId, String text) {
Bitmap bm = BitmapFactory.decodeResource(getResources(), drawableId)
.copy(Bitmap.Config.ARGB_8888, true);
Typeface tf = Typeface.create("Helvetica", Typeface.BOLD);
Paint paint = new Paint();
paint.setStyle(Style.FILL);
paint.setColor(Color.WHITE);
paint.setTypeface(tf);
paint.setTextAlign(Align.CENTER);
paint.setTextSize(convertToPixels(context, 11));
Rect textRect = new Rect();
paint.getTextBounds(text, 0, text.length(), textRect);
Canvas canvas = new Canvas(bm);
//If the text is bigger than the canvas , reduce the font size
if(textRect.width() >= (canvas.getWidth() - 4)) //the padding on either sides is considered as 4, so as to appropriately fit in the text
paint.setTextSize(convertToPixels(context, 7)); //Scaling needs to be used for different dpi's
//Calculate the positions
int xPos = (canvas.getWidth() / 2) - 2; //-2 is for regulating the x position offset
//"- ((paint.descent() + paint.ascent()) / 2)" is the distance from the baseline to the center.
int yPos = (int) ((canvas.getHeight() / 2) - ((paint.descent() + paint.ascent()) / 2)) ;
canvas.drawText(text, xPos, yPos, paint);
return bm;
}
public static int convertToPixels(Context context, int nDP)
{
final float conversionScale = context.getResources().getDisplayMetrics().density;
return (int) ((nDP * conversionScale) + 0.5f) ;
}
and for more information see this link.

So this is how i did it firt i constructed two pics. the marker as shown above and the other one by the following function (all code is found soewhere on stackoverflow):
public static Bitmap getCircleBitmap(Bitmap bm) {
int sice = Math.min((bm.getWidth()), (bm.getHeight()));
Bitmap bitmap = ThumbnailUtils.extractThumbnail(bm, sice, sice);
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(), bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xffff0000;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
paint.setAntiAlias(true);
paint.setDither(true);
paint.setFilterBitmap(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawOval(rectF, paint);
paint.setColor(Color.BLUE);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth((float) 4);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
Then I pass them to the following function
public static Bitmap overlay(Bitmap bmp1, Bitmap bmp2) {
Bitmap bmOverlay = Bitmap.createBitmap(bmp1.getWidth(), bmp1.getHeight(), bmp1.getConfig());
Canvas canvas = new Canvas(bmOverlay);
canvas.drawBitmap(bmp1, new Matrix(), null);
canvas.drawBitmap(bmp2, 5, 5, null);
return bmOverlay;
}
I know its probably not the best way of doing it, especially i dont like the hard coding of the position of the circle in the marker. but t works so far

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));

How might I add a watermark effect to an image in Android?

I have an image with frames and I need to add a watermark effect. How might I do this?

I found great tutorial on Android Image Processing here.
public static Bitmap mark(Bitmap src, String watermark, Point location, Color color, int alpha, int size, boolean underline) {
int w = src.getWidth();
int h = src.getHeight();
Bitmap result = Bitmap.createBitmap(w, h, src.getConfig());
Canvas canvas = new Canvas(result);
canvas.drawBitmap(src, 0, 0, null);
Paint paint = new Paint();
paint.setColor(color);
paint.setAlpha(alpha);
paint.setTextSize(size);
paint.setAntiAlias(true);
paint.setUnderlineText(underline);
canvas.drawText(watermark, location.x, location.y, paint);
return result;
}
Thanks to Pete Houston who shares such useful tutorial on basic image processing.

For others reference, if you want to add the logo of your application (which is in your drawable folder(s)) on top of image use following method:
private Bitmap addWaterMark(Bitmap src) {
int w = src.getWidth();
int h = src.getHeight();
Bitmap result = Bitmap.createBitmap(w, h, src.getConfig());
Canvas canvas = new Canvas(result);
canvas.drawBitmap(src, 0, 0, null);
Bitmap waterMark = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.logo);
canvas.drawBitmap(waterMark, 0, 0, null);
return result;
}

If someone is still searching for this, I found a good solution here
It adds a watermark to the bottom right portion and scales it according to the source image which was exactly what I was looking for.
/**
* Embeds an image watermark over a source image to produce
* a watermarked one.
* #param source The source image where watermark should be placed
* #param watermark Watermark image to place
* #param ratio A float value < 1 to give the ratio of watermark's height to image's height,
* try changing this from 0.20 to 0.60 to obtain right results
*/
public static Bitmap addWatermark(Bitmap source, Bitmap watermark, float ratio) {
Canvas canvas;
Paint paint;
Bitmap bmp;
Matrix matrix;
RectF r;
int width, height;
float scale;
width = source.getWidth();
height = source.getHeight();
// Create the new bitmap
bmp = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
paint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG | Paint.FILTER_BITMAP_FLAG);
// Copy the original bitmap into the new one
canvas = new Canvas(bmp);
canvas.drawBitmap(source, 0, 0, paint);
// Scale the watermark to be approximately to the ratio given of the source image height
scale = (float) (((float) height * ratio) / (float) watermark.getHeight());
// Create the matrix
matrix = new Matrix();
matrix.postScale(scale, scale);
// Determine the post-scaled size of the watermark
r = new RectF(0, 0, watermark.getWidth(), watermark.getHeight());
matrix.mapRect(r);
// Move the watermark to the bottom right corner
matrix.postTranslate(width - r.width(), height - r.height());
// Draw the watermark
canvas.drawBitmap(watermark, matrix, paint);
return bmp;
}
And it is well commented which is what is a huge plus!

It seems you are looking for a waterrippleeffect as this one. Checkout the complete source code. Also check the screenshot how does the effect look like.

In Kotlin:
Note: Its just modified code of above answers
private fun mark(src: Bitmap, watermark: String): Bitmap {
val w = src.width
val h = src.height
val result = Bitmap.createBitmap(w, h, src.config)
val canvas = Canvas(result)
canvas.drawBitmap(src, 0f, 0f, null)
val paint = Paint()
paint.color = Color.RED
paint.textSize = 10f
paint.isAntiAlias = true
paint.isUnderlineText = true
canvas.drawText(watermark, 20f, 25f, paint)
return result
}
val imageBitmap = mark(yourBitmap, "Your Text")
binding.meetProofImageView.setImageBitmap(imageBitmap)

You can use androidWM to add a watermark into your image, even with invisible watermarks:
add dependence:
dependencies {
...
implementation 'com.huangyz0918:androidwm:0.2.3'
...
}
and java code:
WatermarkText watermarkText = new WatermarkText(“Hello World”)
.setPositionX(0.5)
.setPositionY(0.5)
.setTextAlpha(100)
.setTextColor(Color.WHITE)
.setTextFont(R.font.champagne)
.setTextShadow(0.1f, 5, 5, Color.BLUE);
WatermarkBuilder.create(this, backgroundBitmap)
.loadWatermarkText(watermarkText)
.getWatermark()
.setToImageView(backgroundView);
You can easily add an image type watermark or a text watermark like this, and the library size is smaller than 30Kb.

I tried a few libraries mentioned in other posts, like this, but unfortunately it is missing, and not downloadable now. So I followed AndroidLearner 's answer above, but after tweaking the code a little bit, for those of you who are having trouble rotating the watermark, and what values are valid for the various methods of Paint class, so that the text shows rotated at an angle(like most of the company watermarks do), you can use the below code.
Note that, w and h are the screen width and height respectively, which you can calculate easily, there are tons of ways you can find on stackoverflow only.
public static Bitmap waterMarkBitmap(Bitmap src, String watermark) {
int w = src.getWidth();
int h = src.getHeight();
Bitmap mutableBitmap = Utils.getMutableBitmap(src);
Bitmap result = Bitmap.createBitmap(w, h, mutableBitmap.getConfig());
Canvas canvas = new Canvas(result);
canvas.drawBitmap(src, 0f, 0f, null);
Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setTextSize(92f);
paint.setAntiAlias(true);
paint.setAlpha(70); // accepts value between 0 to 255, 0 means 100% transparent, 255 means 100% opaque.
paint.setUnderlineText(false);
canvas.rotate(45, w / 10f, h / 4f);
canvas.drawText(watermark, w / 10f, h / 4f, paint);
canvas.rotate(-45, w / 10f, h / 4f);
return result;
}
It rotates the text watermark by 45 degrees, and places it at the centre of the bitmap.
Also note that, in case you are not able to get watermark, it might be the case that the bitmap you are using as source is immutable. For this worst case scenario, you can use below method to create a mutable bitmap from an immutable one.
public static Bitmap getMutableBitmap(Bitmap immutableBitmap) {
if (immutableBitmap.isMutable()) {
return immutableBitmap;
}
Bitmap workingBitmap = Bitmap.createBitmap(immutableBitmap);
return workingBitmap.copy(Bitmap.Config.ARGB_8888, true);
}
I found above method inside here. I have tested using both the methods in my application, and it works perfectly after I added above tweaks. Try it and let me know if it works or not.

use framelayout. put two imageviews inside the framelayout and specify the position of the watermark imageview.

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.