How to scale Canvas and draw thin border around the edge? - android

I have been struggling to get the preview of a PDF in the Android Print Framework to match the print output. However, I am able to get the output to match as a bitmap. However, if I scale the bitmap and put whitespace around the bitmap, the Print Framework crops out the whitespace. So, to prevent that from happening, I would like to draw a thin border around the edge of the entire Canvas.
This is the code that I have to scale the bitmap:
public static Bitmap captureScreen(View v) {
Bitmap screenshot = null;
Bitmap output = null;
try {
if (v != null) {
screenshot = Bitmap.createBitmap(v.getMeasuredWidth(), v.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
int width = screenshot.getWidth();
int height = screenshot.getHeight();
int scaledWidth = (int) (width * 0.5);
int scaledHeight = (int) (height * 0.5);
output = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Bitmap scaled = Bitmap.createScaledBitmap(screenshot, scaledWidth, scaledHeight, false);
Canvas canvas = new Canvas(output);
Paint paint = new Paint();
int distX = (width - scaledWidth) / 2;
int distY = (height - scaledHeight) / 2;
canvas.drawBitmap(scaled, distX, distY, paint);
v.draw(canvas);
}
} catch (Exception e) {
Log.d("ScreenShotActivity", "Failed to capture screenshot because:" + e.getMessage());
}
return output;
}
I would like to draw a thin black border around the entire canvas for I can prevent the whitespace from being cropped out by the Print Framework.

Well, you have the width and height of the canvas, just call Canvas.drawRect(0, 0, width - 1, height - 1, strokePaint)?

Related

Watermark coming on whole image Android

I want to place the watermark on the bottom right of the picture. But, in some mobiles it is coming perfectly and in some mobile phones, the watermark is coming on the whole image.
Here is my code:
rotatedBitmap = Bitmap.createBitmap(loadedImage, 0, 0,
loadedImage.getWidth(), loadedImage.getHeight(),
rotateMatrix, false);
int w = rotatedBitmap.getWidth();
int h = rotatedBitmap.getHeight();
Bitmap result = Bitmap.createBitmap(w, h, rotatedBitmap.getConfig());
Canvas canvas = new Canvas(result);
canvas.drawBitmap(rotatedBitmap, 0, 0, null);
Bitmap waterMark = BitmapFactory.decodeResource(getResources(), R.drawable.watermark2);
int ww = waterMark.getWidth();
int hh = waterMark.getHeight();
canvas.drawBitmap(waterMark,(w-ww),(h-hh), null);
EDIT: Here are the screenshots of the result. In second picture, the watermark is coming perfectly and in first picture, it is coming on the whole picture.
Make use of aspect ratio. Calculate aspect ratio of device and accordingly calculate appropriate size for your water mark.
How to calculate aspect ratio?
Check for width and height of screen whichever is bigger divide it by smaller one
example:
if(screen_width > screen_height){
aspectRatio = screen_width/screen_height
}else{
aspectRatio = screen_height/screen_width
}
now that you have calculated aspect ratio multiply it with size of you water mark and scale it accordingly.
like:
float ww = watermark.getWidth()*aspectRatio;
float wh = watermark.getHeight()*aspectRatio;
and use these values.
Hope this helps...
Just Give ratio and you go to go,try changing ratio values that best fit for your src bitmap .
Embeds an image watermark over a source image to produce a
watermarked one.
#param source The source image where watermark should be placed
#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(Context context, Bitmap source, float ratio)
{
Canvas canvas;
Paint paint;
Bitmap bmp;
Matrix matrix;
RectF r;
int width, height;
float scale;
Bitmap waterMark = BitmapFactory.decodeResource(context.getResources(), R.drawable.watermark3x);
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());
// Move the watermark to the bottom left corner
// matrix.postTranslate(0 , height - r.height());
// Move the watermark to the top-left corner
// matrix.postTranslate(0 ,0);
// Move the watermark to the top right corner
// matrix.postTranslate(width - r.width(), 0l̥);
// Draw the watermark
canvas.drawBitmap(waterMark, matrix, paint);
return bmp;
}

Transform original bitmap on android

So, I'm using this library https://github.com/thuytrinh/android-collage-views to add "MultiTouchListener" feature to my ImageView. Basically I let user to modify a photo to his needs using rotation, scale and translation. Now the only problem is how to save it. I did it like this:
Bitmap bitmap = Bitmap.createBitmap(imageContainer.getWidth(), imageContainer.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
canvas.drawColor(Color.WHITE);
imageContainer.draw(canvas);
It works, but image is not big enough - it's as big as view on phone so it depends on screen resolution. And I want to "apply" these transformations on given bitmap with full size. And I want transformed image to look like on screen (so it'll need to crop everything out of screen)
I tried the following:
Bitmap newBitmap = Bitmap.createBitmap(image.getWidth(), image.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(newBitmap);
canvas.drawColor(Color.WHITE);
Paint paint = new Paint();
paint.setAntiAlias(true);
canvas.drawBitmap(image, imageView.getMatrix(), paint);
But it doesn't look as expected.
User screen:
And output image (without cropping, because I don't want which side I should crop):
How can I fix this? Is there any solution?
Here is one way to do it, definitely not perfect but should give you a good start :
In this, container refers to the view that contains the transformed ImageView, the phone case on your screenshot and src the raw source bitmap.
First, you need to compute the desired width and height of the output bitmap, i.e the size it would be to make the image fit in it while keeping the ratio of the container :
float containerWidth = containerView.getWidth();
float containerHeight = containerView.getHeight();
float srcWidth = src.getWidth();
float srcHeight = src.getHeight();
float containerRatio = containerWidth / containerHeight;
float srcRatio = srcWidth / srcHeight;
float outputWidth, outputHeight;
if(srcRatio > containerRatio) { //fits in width
outputWidth = srcWidth;
outputHeight = srcWidth / containerRatio;
}
else if(srcRatio < containerRatio) { //fits in height
outputHeight = srcHeight;
outputWidth = srcHeight * containerRatio;
}
else {
outputWidth = srcWidth;
outputHeight = srcHeight;
}
Apply the ratio between container width/height and output width/height to the translation part of the matrix that hold the transformation that the user did
float containerToOutputRatioWidth = outputWidth / containerWidth;
float containerToOutputRatioHeight = outputHeight / containerHeight;
float[] values = new float[9];
transformedImageView.getMatrix().getValues(values);
values[2] = values[2] * containerToOutputRatioWidth;
values[5] = values[5] * containerToOutputRatioHeight;
Matrix outputMatrix = new Matrix();
outputMatrix.setValues(values);
Draw the output bitmap as you were doing with the correct size (outputWidth, outputHeight) and matrix (outputMatrix).
Bitmap newBitmap = Bitmap.createBitmap(Math.round(outputWidth), Math.round(outputHeight), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(newBitmap);
canvas.drawColor(Color.WHITE);
Paint paint = new Paint();
paint.setAntiAlias(true);
canvas.drawBitmap(src, outputMatrix, paint);
.
Warnings
You should be careful about memory allocation, this code will lead to allocate some massive bitmaps, you should implement some kind of limit that get along with your needs. (Also do allocation and drawing in background)
You might need to do some adjustment depending on where you place the image in the first place.

Android - Cut bitmap starting from some point

I've been searching here about cut bitmaps in android, however I could not make it work for me.
I would like to cut off some part of one specific bitmap, but I want to do that starting from center to the bottom of my image.
I already tried to use:
createBitmap(android.graphics.Bitmap source, int x, int y, int width, int height)
However, it always start to cut my image from the TOP, even changing x and y values.
I want to cut my bitmap as below blue square.
Someone have any idea about how to cut my bitmap?
You should take a look at this:
private Bitmap cropBitmap1()
{
Bitmap bmp2 = BitmapFactory.decodeResource(this.getResources(), R.drawable.image1);
Bitmap bmOverlay = Bitmap.createBitmap(320, 480, Bitmap.Config.ARGB_8888);
Paint p = new Paint();
p.setXfermode(new PorterDuffXfermode(Mode.CLEAR));
Canvas c = new Canvas(bmOverlay);
c.drawBitmap(bmp2, 0, 0, null);
c.drawRect(30, 30, 100, 100, p);
return bmOverlay;
}
Link: Source
Try this:
Bitmap source = BitmapFactory.decodeResource(getResources(),
R.drawable.ic_launcher);
int width = source.getWidth();
int height = source.getHeight();
int required = 25;// 25 pixels width and height
int startX = (width - required) / 2;
int startY = (height - required) / 2;
Bitmap resized = Bitmap.createBitmap(source, startX, startY, required,
required);
The only relevant part is the startX and startY calculations. The code asumes that you need a 25*25 pixels image.

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.

How to create white border around bitmap?

For example I want a white border of 10pixel around all 4 side of the bitmap. I am not using it for imageview
I am currently using this code to crop image. May I know how I could add a white border into it?
public Bitmap scaleCenterCrop(Bitmap source, int newHeight, int newWidth) {
int sourceWidth = source.getWidth();
int sourceHeight = source.getHeight();
// Compute the scaling factors to fit the new height and width, respectively.
// To cover the final image, the final scaling will be the bigger
// of these two.
float xScale = (float) newWidth / sourceWidth;
float yScale = (float) newHeight / sourceHeight;
float scale = Math.max(xScale, yScale);
// Now get the size of the source bitmap when scaled
float scaledWidth = scale * sourceWidth;
float scaledHeight = scale * sourceHeight;
// Let's find out the upper left coordinates if the scaled bitmap
// should be centered in the new size give by the parameters
float left = (newWidth - scaledWidth) / 2;
float top = (newHeight - scaledHeight) / 2;
// The target rectangle for the new, scaled version of the source bitmap will now
// be
RectF targetRect = new RectF(left, top, left + scaledWidth, top + scaledHeight);
// Finally, we create a new bitmap of the specified size and draw our new,
// scaled bitmap onto it.
Bitmap dest = Bitmap.createBitmap(newWidth, newHeight, source.getConfig());
Canvas canvas = new Canvas(dest);
canvas.drawBitmap(source, null, targetRect, null);
return dest;
}
I wrote a function for this:
private Bitmap addWhiteBorder(Bitmap bmp, int borderSize) {
Bitmap bmpWithBorder = Bitmap.createBitmap(bmp.getWidth() + borderSize * 2, bmp.getHeight() + borderSize * 2, bmp.getConfig());
Canvas canvas = new Canvas(bmpWithBorder);
canvas.drawColor(Color.WHITE);
canvas.drawBitmap(bmp, borderSize, borderSize, null);
return bmpWithBorder;
}
Basically it creates a new Bitmap adding 2 * bordersize to each dimension and then paints the original Bitmap over it, offsetting it with bordersize.
As for a way of doing this. You make your bitmap bigger than the one your adding to it and then fill the canvas with the background you want. If you need to add other effects you can look into the canvas options for clipping the rect and adding rounded corners and such.
RectF targetRect = new RectF(left+10, top+10, left + scaledWidth, top + scaledHeight);
Bitmap dest = Bitmap.createBitmap(newWidth+20, newHeight+20, source.getConfig());
Canvas canvas = new Canvas(dest);
canvas.drawColor(Color.WHITE);
canvas.drawBitmap(source, null, targetRect, null);
You can draw 4 rectangles after painting your bitmap's stuff.
point 0,0,3,sizey
point 0,0,sizex,3
point 0,sizey-3,sizex,sizey
point sizex-3,0,sizex,sizey
the accepted answer is nice but in the cases that bitmap contains a transparent background, it fills all over the background of source bitmap with white pixels. so it doesn't work fine for all cases.
a better way to achieve this goal is using Canvas#drawLine method like the following code:
Bitmap drawBorder(Bitmap source) {
int width = source.getWidth();
int height = source.getHeight();
Bitmap bitmap = Bitmap.createBitmap(width, height, source.getConfig());
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setStrokeWidth(50);
paint.setColor(Color.WHITE);
canvas.drawLine(0, 0, width, 0, paint);
canvas.drawLine(width, 0, width, height, paint);
canvas.drawLine(width, height, 0, height, paint);
canvas.drawLine(0, height, 0, 0, paint);
canvas.drawBitmap(source, 0, 0, null);
return bitmap;
}
in this way we first create a second bitmap using source bitmap width, height and config and use drawline() mathod four times to draw four lines using coordinates of end points of each line around the second bitmap and then draw the source bitmap on the second bitmap that must be returned.
A super easy way of doing it would be to set the ImageView background to white and add a padding value.
If that doesn't work, create a FrameLayout with w/h of wrap_content, set its background to white, put the ImageView in there, and set the ImageView's margins to the desired border width.
Its not elegant but you can always just draw a rectangle behind it, you already have the code to do this and any performance impact is going to be unnoticeable
You can create your targetRectangle 20px wider and 20px higher
RectF targetRect = new RectF(left, top, left + scaledWidth + 20, top + scaledHeight + 20);
and paint the background white
Try this it will also add border to your canvas
canvas.drawLine(0, 0, canvas.getWidth(), 0, paint2);
canvas.drawLine(0, 0, 0, canvas.getHeight(), paint2);
canvas.drawLine(0, canvas.getHeight(), canvas.getWidth(),
canvas.getHeight(), paint2);
canvas.drawLine(canvas.getWidth(), 0, canvas.getWidth(),
canvas.getHeight(), paint2);

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