I tried to paint a rotated bitmap with anti alias turned on, but it still has alias and it's not smooth, any help?
I did as following:
final Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
p.setAntiAlias(true);
canvas.rotate(-mValues[0]);
canvas.drawBitmap(compass, -compass.getWidth()/2,-compass.getHeight()/2,p);
Paint.setAntiAlias() is for text.
You want p.setFilterBitmap(true);.
In case you're rotating without a canvas (with createBitmap), set filter to true.
Example:
private static Bitmap rotateBitmap(Bitmap srcImage, float angle) {
Matrix matrix = new Matrix();
matrix.postRotate(angle);
Bitmap rotated = Bitmap.createBitmap(srcImage, 0, 0, srcImage.getWidth(), srcImage.getHeight(), matrix, true/*set true for anti-alias*/);
srcImage.recycle(); // discard original image
return rotated;
}
Related
I've been looking for over a day for a solution to this problem but nothing helps, even the answers here. Documentation doesn't explain anything too.
I am simply trying to get a rotation in the direction of another object. The problem is that the bitmap is not rotated around a fixed point, but rather around the bitmaps (0,0).
Here is the code I am having troubles with:
Matrix mtx = new Matrix();
mtx.reset();
mtx.preTranslate(-centerX, -centerY);
mtx.setRotate((float)direction, -centerX, -centerY);
mtx.postTranslate(pivotX, pivotY);
Bitmap rotatedBMP = Bitmap.createBitmap(bitmap, 0, 0, spriteWidth, spriteHeight, mtx, true);
this.bitmap = rotatedBMP;
The weird part is, it doesn't matter how I change the values within pre/postTranslate() and the float arguments in setRotation(). Can someone please help and push me in the right direction? :)
I hope the following sequence of code will help you:
Bitmap targetBitmap = Bitmap.createBitmap(targetWidth, targetHeight, config);
Canvas canvas = new Canvas(targetBitmap);
Matrix matrix = new Matrix();
matrix.setRotate(mRotation,source.getWidth()/2,source.getHeight()/2);
canvas.drawBitmap(source, matrix, new Paint());
If you check the following method from ~frameworks\base\graphics\java\android\graphics\Bitmap.java
public static Bitmap createBitmap(Bitmap source, int x, int y, int width, int height,
Matrix m, boolean filter)
this would explain what it does with rotation and translate.
Edited: optimized code.
public static Bitmap RotateBitmap(Bitmap source, float angle)
{
Matrix matrix = new Matrix();
matrix.postRotate(angle);
return Bitmap.createBitmap(source, 0, 0, source.getWidth(), source.getHeight(), matrix, true);
}
To get Bitmap from resources:
Bitmap source = BitmapFactory.decodeResource(this.getResources(), R.drawable.your_img);
I came back to this problem now that we are finalizing the game and I just thought to post what worked for me.
This is the method for rotating the Matrix:
this.matrix.reset();
this.matrix.setTranslate(this.floatXpos, this.floatYpos);
this.matrix.postRotate((float)this.direction, this.getCenterX(), this.getCenterY());
(this.getCenterX() is basically the bitmaps X position + the bitmaps width / 2)
And the method for Drawing the bitmap (called via a RenderManager Class):
canvas.drawBitmap(this.bitmap, this.matrix, null);
So it is prettey straight forward but I find it abit strange that I couldn't get it to work by setRotate followed by postTranslate. Maybe some knows why this doesn't work? Now all the bitmaps rotate properly but it is not without some minor decrease in bitmap quality :/
Anyways, thanks for your help!
You can also rotate the ImageView using a RotateAnimation:
RotateAnimation rotateAnimation = new RotateAnimation(from, to,
Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
0.5f);
rotateAnimation.setInterpolator(new LinearInterpolator());
rotateAnimation.setDuration(ANIMATION_DURATION);
rotateAnimation.setFillAfter(true);
imageView.startAnimation(rotateAnimation);
You can use something like following:
Matrix matrix = new Matrix();
matrix.setRotate(mRotation,source.getWidth()/2,source.getHeight()/2);
RectF rectF = new RectF(0, 0, source.getWidth(), source.getHeight());
matrix.mapRect(rectF);
Bitmap targetBitmap = Bitmap.createBitmap(rectF.width(), rectF.height(), config);
Canvas canvas = new Canvas(targetBitmap);
canvas.drawBitmap(source, matrix, new Paint());
Look at the sample from Google called Lunar Lander, the ship image there is rotated dynamically.
Lunar Lander code sample
I used this configurations and still have the problem of pixelization :
Bitmap bmpOriginal = BitmapFactory.decodeResource(this.getResources(), R.drawable.map_pin);
Bitmap targetBitmap = Bitmap.createBitmap((bmpOriginal.getWidth()),
(bmpOriginal.getHeight()),
Bitmap.Config.ARGB_8888);
Paint p = new Paint();
p.setAntiAlias(true);
Matrix matrix = new Matrix();
matrix.setRotate((float) lock.getDirection(),(float) (bmpOriginal.getWidth()/2),
(float)(bmpOriginal.getHeight()/2));
RectF rectF = new RectF(0, 0, bmpOriginal.getWidth(), bmpOriginal.getHeight());
matrix.mapRect(rectF);
targetBitmap = Bitmap.createBitmap((int)rectF.width(), (int)rectF.height(), Bitmap.Config.ARGB_8888);
Canvas tempCanvas = new Canvas(targetBitmap);
tempCanvas.drawBitmap(bmpOriginal, matrix, p);
matrix.reset();
matrix.setTranslate( anchor.x, anchor.y );
matrix.postRotate((float) rotation , 0,0);
matrix.postTranslate(positionOfAnchor.x, positionOfAnchor.x);
c.drawBitmap(bitmap, matrix, null);
I am trying to translate a image using matrix my code is
Bitmap myImg = BitmapFactory.decodeResource(getResources(), R.drawable.calednder_c);
Matrix matrix = new Matrix();
matrix.setTranslate(500,300 );
Bitmap rotated = Bitmap.createBitmap(myImg, 0, 0, myImg.getWidth(), myImg.getHeight(),
matrix, true);
circle.setImageBitmap(rotated);
when i am calling my animate method nothing happening .while i wrote preRotate(angle); it rotate and it scale also but not translate why what i am missing
Thanks in advance
Here is the respective snippet from the createBitmap source code:
final boolean transformed = !m.rectStaysRect();
RectF deviceR = new RectF();
m.mapRect(deviceR, dstR);
neww = Math.round(deviceR.width());
newh = Math.round(deviceR.height());
bitmap = createBitmap(neww, newh, transformed ? Config.ARGB_8888 : newConfig,
transformed || source.hasAlpha());
canvas.translate(-deviceR.left, -deviceR.top);
canvas.concat(m);
paint = new Paint();
paint.setFilterBitmap(filter);
if (transformed) {
paint.setAntiAlias(true);
}
It makes the created bitmap just big enough to hold all the desired pixels from the original bitmap. This is caused by the new size and the canvas.translate call.
The net effect is that translations in the matrix are ignored.
I'm trying to rotate an overlay drawable to represent an overlay item in Android.
I use this:
Bitmap bmpOriginal = BitmapFactory.decodeResource(this.getResources(), R.drawable.map_pin);
Bitmap targetBitmap = Bitmap.createBitmap((bmpOriginal.getWidth()),
(bmpOriginal.getHeight()),
Bitmap.Config.ARGB_8888);
Matrix matrix = new Matrix();
matrix.setRotate((float) lock.getDirection(),(float) (bmpOriginal.getWidth()/2),
(float)(bmpOriginal.getHeight()/2));
Canvas tempCanvas = new Canvas(targetBitmap);
tempCanvas.drawBitmap(bmpOriginal, matrix, null);
Drawable d = new BitmapDrawable(getResources(),targetBitmap);
//overlayitem.setMarker(drawable);
mapItemizedOverlay =
new MyItemizedOverlay<MyItemizedOverlayItem>(d, mapView);
The problem is that the image quality worsens. Pixelization happens. Any solution?
This code worked perfectly with me
Bitmap bmpOriginal = BitmapFactory.decodeResource(this.getResources(), R.drawable.map_pin);
Bitmap targetBitmap = Bitmap.createBitmap((bmpOriginal.getWidth()),
(bmpOriginal.getHeight()),
Bitmap.Config.ARGB_8888);
Paint p = new Paint();
p.setAntiAlias(true);
p.setDither(true);
p.setFilterBitmap(true);
Matrix matrix = new Matrix();
matrix.setRotate((float) lock.getDirection(),(float) (bmpOriginal.getWidth()/2),
(float)(bmpOriginal.getHeight()/2));
RectF rectF = new RectF(0, 0, bmpOriginal.getWidth(), bmpOriginal.getHeight());
matrix.mapRect(rectF);
targetBitmap = Bitmap.createBitmap((int)rectF.width(), (int)rectF.height(), Bitmap.Config.ARGB_8888);
Canvas tempCanvas = new Canvas(targetBitmap);
tempCanvas.drawBitmap(bmpOriginal, matrix, p);
You could try to apply a paint with antialiasing but if its about pixels within the bitmap the only chance is filtering and android has its limits. Depending on the bitmap you might never be able to get it really smooth, i did try a lot but never found anything that would give it a real nice finish
public static Bitmap createScaledBitmap (Bitmap src, int dstWidth, int dstHeight, boolean filter)
the filter boolean should be true, thats all that you can do for filtering afaik
void android.graphics.Canvas.drawBitmap(Bitmap bitmap, Rect src, RectF dst, Paint paint)
here you can apply a paint, you can experiment with settings on this paint, but anti-alias will work on the edges of the bitmap. Shader settings might work on the bitmap as well but there are no shaders that can fix the rotation inaccuracy
Add the following:
Paint p = new Paint();
p.setAntiAlias(true);
p.setDither(true);
p.setFilterBitmap(true);
change the following:
tempCanvas.drawBitmap(bmpOriginal, matrix, null);
to:
tempCanvas.drawBitmap(bmpOriginal, matrix, p);
I have tried several hours to rotate a bitmap with no success. I have read numerous articles about this subject on this web site and it seems the prefered solution involves creating a temporary canvas. Well I did this and I still do not see a roated bitmap.
My bitmap is a 40x40 blue square and I am trying to rotate it 45 degrees. Thats not asking for much is it? When the code runs, the bitmap that appears on the screen is the non-rotated original. ( I have also tried a translate with no success as well)
Here is my code:
// Load the bitmap resource
fillBMP2 = BitmapFactory.decodeResource(context.getResources(), R.drawable.test1);
// Copy to a mutable bitmap
mb = fillBMP2.copy(Bitmap.Config.ARGB_8888, true);
// Create canvas to draw to
Canvas offscreenCanvas = new Canvas (mb);
// Create Matrix so I can rotate it
Matrix matrix = new Matrix();
matrix.setRotate (45);
offscreenCanvas.setMatrix (matrix);
// Send the contents of the canvas into a bitmap
offscreenCanvas.setBitmap(mb);
Later in an OnDraw I do the following:
canvas.drawBitmap(mb, 200, 200, null);
Any ideas what I am doing wrong? Seems like it should work.
Thanks
Try using this
Matrix matrix = new Matrix();
matrix.setRotate(15);
canvas.drawBitmap(bmp, matrix, paint);
setRotation method takes in a float representing
the degrees of rotation.
Try this...
Matrix matrix = new Matrix();
float px = 200;
float py = 200;
matrix.postTranslate(-bitmap.getWidth()/2, -bitmap.getWidth()/2);
matrix.postRotate(45);
matrix.postTranslate(px, py);
canvas.drawBitmap(bitmap, matrix, paint);
You definitely want to use transformations: check out this link.
Basically it's this:
// save the canvas
ctx.save();
// move origin to center
ctx.translate(x,y);
// rotate
ctx.rotate(angle * (Math.PI / 180));
// draw image
ctx.drawImage(image, x, y, w, h, .w/2, h/2, w, h);
// restore
ctx.restore();
public Drawable rotateDrawable(int angle)
{
Bitmap arrowBitmap = BitmapFactory.decodeResource(mContext.getResources(), R.drawable.arrowscalled);
// Create blank bitmap of equal size
Bitmap canvasBitmap = arrowBitmap.copy(Bitmap.Config.ARGB_8888, true);
canvasBitmap.eraseColor(0x00000000);
// Create canvas
Canvas canvas = new Canvas(canvasBitmap);
// Create rotation matrix
Matrix rotateMatrix = new Matrix();
rotateMatrix.setRotate(angle, canvas.getWidth()/2, canvas.getHeight()/2);
// Draw bitmap onto canvas using matrix
canvas.drawBitmap(arrowBitmap, rotateMatrix, null);
return new BitmapDrawable(canvasBitmap);
}
Whenever I call this the marker dissapears instead of rotating. What am I doing wrong?
Instead of going through the hassle of creating a new Canvas and all that use Bitmap.createBitmap (Bitmap source, int x, int y, int width, int height, Matrix m, boolean filter). When you create your rotation matrix, use half the width and height passed to the createBitmap function. After this create your BitmapDrawable.