I currently have a button template (layout) as XML, where I load it off resources in my code and dynamically create the button.
So here's the question, is there any possible way to crop/cut the buttons' (or any view for that matter) into a specific shape?
Let's say I have a rectangle button, am I able to cut it to create some triangular form with it? here's an example:
What are the possibilities on there without having to create a custom Bitmap for it? (since the XML uses specific stroke/radius stuff which wouldn't work correctly on a Bitmap)
Is it possible for it to keep its size and margins even after the cuts? I'm really interested to know.
Thanks in advance to anyone willing to help!
You can use Canvas for what you want. It will allow you to modify the view by drawing shapes, erasing some area etc.
For example, following function will return a circular cropped bitmap of the initial bitmap provided:
public Bitmap getCroppedBitmap(Bitmap bitmap) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
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);
canvas.drawCircle((bitmap.getWidth() / 2), (bitmap.getHeight() / 2),
(output.getWidth() / 2), paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
canvas = null;
paint = null;
// bitmap.recycle();
return output;
}
To convert view into bitmap, see this.
Related
I'm developing an Android application and I would like to blend Bitmap with a filter like "Multiply" or "Difference" from Photoshop. Bitmap1 is translating horizontally and Bitmap2 vertically.
I had few ideas :
1) Create a method which do some calculation to find the intersection part of the two Bitmap (Requires to cross 2 matrix every frame, very heavy, seems impossible ?). Then crop the intersection on the 2 Bitmap, blend them, and finally draw it. Another idea would be to do a ANDing between the two Bitmap, maybe faster than the other method, does thi function already exist ?
2) OpenGL ES ? But I really don't understand how to use it.
3) But recently I have found this sample code which blend two Bitmap on a canvas and use a paint. The result is the one I want BUT there is still no animation. So I've create a new Class (extends View) in addition to this activity, with the method onDraw(Canvas canvas).
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_compo);
Bitmap bm1 = BitmapFactory.decodeResource(getResources(), R.drawable.bm1);
Bitmap bm2 = BitmapFactory.decodeResource(getResources(), R.drawable.bm2);
blend(bm1,bm2);
}
private void blend(Bitmap bm1, Bitmap bm2){
DisplayMetrics metrics = new DisplayMetrics();
this.getWindowManager().getDefaultDisplay().getMetrics(metrics);
int h = metrics.heightPixels;
int w = metrics.widthPixels;
/// BLEND MODE ///
// Create result image
Bitmap.Config conf = Bitmap.Config.ARGB_8888; // see other conf types
Bitmap result = Bitmap.createBitmap(w, h, conf);
Canvas canvas = new Canvas();
canvas.setBitmap(result);
// Get proper display reference
BitmapDrawable drawable = new BitmapDrawable(getResources(), result);
ImageView imageView = (ImageView)findViewById(R.id.photo1);
imageView.setImageDrawable(drawable);
// Draw base
canvas.drawBitmap(bm2, 0, 0, null);
// Draw overlay
Paint paint = new Paint();
paint.setXfermode(new PorterDuffXfermode(Mode.MULTIPLY));
paint.setShader(new BitmapShader(bm1, TileMode.CLAMP, TileMode.CLAMP));
canvas.drawRect(700, 700, bm2.getWidth(), bm2.getHeight(), paint);
}
Here is the result with changing the value in 'canvas.drawRect()' :
Before translation
After translation
Do you have other solutions ? Or suggestions which would help to realize my filter on animate views ? (The perfect solutions would be to add something like android:blendMode="Multiply" in the XML, but it doesn't seem as easy)
Thank you in advance. J'.
So I seem to have a conundrum. I need to add multiple custom views to a framelayout. The code for this is working just fine. However, I wish to access the underlying bitmap that the canvas uses in the views onDraw method. Like this one (in a class that extends View):
#Override
protected void onDraw(Canvas canvas) {
// TODO Auto-generated method stub
super.onDraw(canvas);
canvas.drawARGB(Color.alpha(bgColor), Color.red(bgColor),
Color.green(bgColor), Color.blue(bgColor));
m.reset();
m.setTranslate(imgPosX - ((float) userImage.getWidth() / 2.0f), imgPosY
- ((float) userImage.getHeight() / 2.0f));
m.postRotate(angle);
m.postScale(1.0f, 1.0f);
canvas.drawBitmap(userImage, m, null);
}
I wish to erase certain pixels essentially. Now, I know I can do this via the setPixel method which is fine but it is exceptionally slow and not satisfactory. I have a working ndk function that does exactly what I want, but it passes in a bitmap. I know I can use a SurfaceView instead of a View to access the bitmap like that, however as mentioned here multiple SurfaceViews in a FrameLayout isn't an option. So, I would think I need to manipulate the bitmap itself used by the canvas in the onDraw method. How would I go about doing this? or alternatively I don't mind creating another bitmap, passing it into the ndk function and returning/drawing that, however would I do a canvas.drawBitmap with transparent pixels?
Have you looked into setting the PorterDuff mode on a Paint object?
use paint.setXfermode(new PorterDuffXfermode(Mode.CLEAR)) then draw over the pixels that you want to erase
edit: What exactly are you trying to clear? There are multiple modes and you may need to select a different one depending on what you are trying to do. Here is an example of a function I currently use to crop Bitmaps to a circle.
public static Bitmap crop_circle_center(Bitmap bitmap) {
final int diameter = Math.min(bitmap.getWidth(), bitmap.getHeight());
Bitmap output = Bitmap.createBitmap(diameter,
diameter, 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());
rect.offset(-(bitmap.getWidth()-diameter)/2, -(bitmap.getHeight()-diameter)/2);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawCircle(diameter/ 2, diameter/ 2,
diameter / 2, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, null, rect, paint);
return output;
}
I have an image, I can draw an circle over it like the code below:
Bitmap bitmap = BitmapFactory.decodeResource(getResources(),
R.drawable.girl).copy(Bitmap.Config.ARGB_8888, true);
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setStrokeWidth(200);
paint.setStyle(Style.STROKE.FILL);
paint.setAntiAlias(true);
canvas.drawCircle(bitmap.getWidth() / 2, bitmap.getHeight() / 2, 100,
paint);
And the circle will be red color! But because of some reason, I want the color of circle same as its under bitmap. Can I do it? and how? Thanks everyone!
Edited: One more question, How I can get all the pixels inside circle?
why dont you simply remove the paint.setStyle(Style.STROKE.FILL); or try changing the paint.setColor(Color.RED); to Transparent color, that should be it
you can get the color of a specified pixel by the method in this article and then make a RGB Color then set this color instead of the color.RED you mentioned.
The following code defines my Bitmap:
Resources res = context.getResources();
mBackground = BitmapFactory.decodeResource(res, R.drawable.background);
// scale bitmap
int h = 800; // height in pixels
int w = 480; // width in pixels
// Make sure w and h are in the correct order
Bitmap scaled = Bitmap.createScaledBitmap(mBackground, w, h, true);
... And the following code is used to execute/draw it (the unscaled Bitmap):
canvas.drawBitmap(mBackground, 0, 0, null);
My question is, how might I set it to draw the scaled Bitmap returned in the form of Bitmap scaled, and not the original?
Define a new class member variable:
Bitmap mScaledBackground;
Then, assign your newly created scaled bitmap to it:
mScaledBackground = scaled;
Then, call in your draw method:
canvas.drawBitmap(mScaledBackground, 0, 0, null);
Note that it is not a good idea to hard-code screen size in the way you did in your snippet above. Better would be to fetch your device screen size in the following way:
int width = getWindowManager().getDefaultDisplay().getWidth();
int height = getWindowManager().getDefaultDisplay().getHeight();
And it would be probably better not to declare a new bitmap for the only purpose of drawing your original background in a scaled way. Bitmaps consume a lot of precious resources, and usually a phone is limited to a few MB of Bitmaps you can load before your app ungracefully fails. Instead you could do something like this:
Rect src = new Rect(0, 0, bitmap.getWidth() - 1, bitmap.getHeight() - 1);
Rect dest = new Rect(0, 0, width - 1, height - 1);
canvas.drawBitmap(mBackground, src, dest, null);
To draw the scaled bitmap you want save your scaled bitmap in a field somewhere (here called mScaled) and call:
canvas.drawBitmap(mScaled, 0, 0, null);
in your draw method (or wherever you call it right now).
I have an android application in which I need to download text from a website, convert it into bitmap format and display it on an LED-based display board.
I am struggling with the bitmap conversion.
Tried to use the following:
Bitmap mybitmap = Bitmap.createBitmap(100, 16, Bitmap.Config.ALPHA_8);
Canvas c = new Canvas(mybitmap);
c.drawText("0", 0, 0, paint);
But it doesn't seem to be working. Any suggestions?
Update:
Paint object is initialized like this:
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.RED);
paint.setTextSize(16);
paint.setAntiAlias(true);
paint.setTypeface(Typeface.MONOSPACE);
I think you draw outside the image. Try setting y to 16.
c.drawText("0", 0, 16, paint);
Note that when drawing text the coordinate origin is the lower left coordinate corner.