I have a mutable Bitmap and I'm drawing it on a Canvas. After that I want to draw a pre-defined text on the bitmap. The problem is I have different bitmap sizes, even though I'm setting the text size to 20sp, depending on the bitmap size the text is bigger of smaller, but I want the text size to be the same for ALL images. What Should I do? I thought of maybe scaling the text size depending on the image width and weight but I'm not sure how to do that.
final Bitmap mutableBitmap = bitmap.copy(Bitmap.Config.ARGB_8888, true);
final Canvas canvas = new Canvas(mutableBitmap);
final Paint paint = new Paint();
paint.setTextSize(getResources().getDimensionPixelSize(R.dimen.myFontSize);
canvas.drawText(text, x, y, paint);
First of if this is your onDraw method you are doing wrong work here. You shouldn't allocate anything inside the onDraw method. On the other hand , you shouldn't change your text size for bitmaps. Resize your bitmaps on same values(width and height) , then setting the text for same value.
Related
I want to be able to slowly make a bitmap image more and more transparent on my canvas.
Currently I am drawing the .png file (stored in drawables) like this:
//I setup the Bitmap in my constructor.
heartSymb = BitmapFactory.decodeResource(getResources(),R.drawable.heartsymbol);
//This is in on draw.
canvas.drawBitmap(heartSymb,0,0,null);
How would I be able to slowly change the bitmap's transparency until it becomes fully transparent?
You can use a Paint object to modify the alpha of the bitmap to be drawn:
Paint alphaPaint = new Paint();
alphaPaint.setAlpha(alpha);
canvas.drawBitmap(heartSymb, 0, 0, alphaPaint);
Then you just have to modify alpha value and perform update periodically, maybe by using a Handler.
I have a 200x200px bitmap. I want to draw the top left 50x50px corner of my bitmap, on my canvas at coordinates 100,100 with a width and height of 50px, by using:
drawBitmap(Bitmap bitmap, Rect src, Rect dst, Paint paint)
This is what I've tried:
drawBitmap(myBitmap, new Rect(0,0,50,50), new Rect(100,100,150,150) , null);
What am I doing wrong?
From developer.android.com:
Parameters
bitmap The bitmap to be drawn
src May be null. The subset of the bitmap to be drawn
dst The rectangle that the bitmap will be scaled/translated to fit into
paint May be null. The paint used to draw the bitmap
What is missing in my code?
Thanks!
You need to change your rectangles. This is because, as described in the documentation, the first rectangle is the subset of the bitmap you want to draw, the second is the scaling/translating so basically the size of the destination draw (50x50)
So it should look like this:
drawBitmap(myBitmap, new Rect(100,100,150,150), new Rect(0,0,50,50) , null);
I am drawing paths on canvas and creating Transparent bitmap while saving and creating cropping bitmap from transparent bitmap.
See Images :
In this I mage I am drawing path on canvas and I am creating transparent bitmap and according to startX,lowestY and highestX,highestY
Bitmap cropBitmap =Bitmap.createBitmap(sourceBitmap,startX,lowestY,highestX,highestY);
When I am cropping Bitmap I want Only "Test" drawing crop bitmap.But it's giving empty bitmap. Like this
Inside red box I want cropped bitmap from transparent bitmap whatever I draw on canvas.
You cannot simply create a transparent bitmap, and assume that whatever is within the bounds of the bitmap has become a part of it meaning that the pixels are identical. There are two problems with your assumption, number 1, a transparent bitmap won't help because transparency serves as a see through bitmap which only will have alpha value, number 2, the data that is drawn with the path, has no correlation to the data of your bitmap, you initially created a bitmap with no color, except that it's completely transparent.
Here's the general code for the correct way how to achieve such a task:
class myDrawingView extends View() {
// all your class members you initialize here
#Override
public void onDraw(Canvas canvas) {
// get your width and height using startx, starty, highestx, highesty, lowesty
Bitmap buffer = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
canvas.setBitmap(buffer);
canvas.drawPath(//draw your path here);
invalidate();
}
The Bitmap called buffer, now is the frame buffer for all your drawing so you can draw a path and that will be rendered on the buffer you defined. And you see that no transparency was used we just simply created a bitmap with no pixels assigned to it at first, once you draw to it via the canvas, your bitmaps pixels will be whatever you drew.
I am trying to draw multiline text to a bitmap with the font Latto-Reg, and StaticLayout seems to have problems with it.
paint.setTextSize(label.fontSize);
paint.setTypeface(face);
StaticLayout textLayout = new StaticLayout(label.text, paint, (int)StaticLayout.getDesiredWidth(label.text, paint), Alignment.ALIGN_NORMAL, 1.0f, 0.0f, false);
Bitmap bitmapAux = Bitmap.createBitmap(textLayout.getEllipsizedWidth(), textLayout.getHeight(), Bitmap.Config.ALPHA_8);
canvas.setBitmap(bitmapAux);
canvas.save();
canvas.translate(0, textLayout.height());
textLayout.draw(canvas);
canvas.restore();
The texture has padding on top and bottom depending on the font and size, while the text fits perfectly in the bitmap it is a lot of wasted memory space and makes laying it out to be off by a random amount.
I tested using single-line drawing and the bitmap was perfectly fitting the text
paint.getTextBounds(label.text, 0, label.text.length(), rect);
Bitmap bitmapAux = Bitmap.createBitmap(rect.width(), rect.height(), Bitmap.Config.ALPHA_8);
canvas.drawText(label.text, -rect.left, -rect.bottom, paint);
I have tried getting all kinds of metrics from StaticLayout and all of them seem to be off from the text: line 0 bounds, line 0 top, last line bottom...leading to the same padding problems.
EDIT:
I solved the problem by using offset-based single line drawing. Still the StaticLayout class was drawing incorrectly with several different non-standard fonts and I want to know why.
Looking at the android developper page, it looks like it's designed to handle both the multi-line case and being used next to another Layout well, and hence there is space on top of the line of text so that if you place it directly below another Layout it will be correctly spaced. In essence, it's just not designed for what you are trying to achieve.
Overall, it may be easier to get the Text bounds from Paint.getTextBounds() to know what the extent of the text will be within the Layout.
I've created a minimal working example of what I think you're trying to accomplish: creating a bitmap precisely large enough to contain the text rendered through a StaticLayout.
It seems that there are a few things wrong with your code:
You're needlessly translating vertically inside the bitmap;
There doesn't appear to be a height() method for StaticLayout.
Here's my result:
I added a green background to illustrate the size of the bitmap, but otherwise, my code differs very little from yours:
public void createTexture() {
int width = textLayout.getEllipsizedWidth();
int height = textLayout.getHeight();
bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas canvas2 = new Canvas(bitmap);
Paint p2 = new Paint();
p2.setStyle(Style.FILL);
p2.setColor(Color.GREEN);
canvas2.drawRect(0, 0, width, height, p2);
textLayout.draw(canvas2);
}
I created a very simple custom component to draw the bitmap:
#Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(bitmap, 0, 0, paint);
}
It seems that perhaps you're translating to draw multiple textures after one another. I'd recommend that you do so in your draw method instead, translating vertically in the height of the previous texture after drawing it.
Is there anyway to increase Canvas size more then my screen size in Android? Like if my screen size is 320 x 480 I want to increase my canvas size 3 times bigger then that.
You can create a bitmap of desired size and then draw needed part of it to canvas using drawBitmap (Bitmap bitmap, Rect src, Rect dst, Paint paint) method of canvas.