Develop Reference

Increase bitmap size without scaling image

I would like to increase the size of a Bitmap in my Android application.
It sounds like a very simple operation but I cannot find how to do so anywhere.
Here is an image to illustrate what I am trying to achieve here:
Basically, I'd like to create a new bitmap that has the same width as the original, but a bigger height. The background of the (new) extra pixels can be black, white or transparent.
How can I do this?

Some like this should do.
// Create a Canvas to draw to
Canvas bitmapCanvas = new Canvas();
// Create a Bitmap to back the Canvas of the new size
Bitmap bitmap = Bitmap.createBitmap(X, Z, Bitmap.Config.ARGB_8888);
bitmapCanvas.setBitmap(bitmap);
// Calculate the new position of bitmap
// Middle of new Z dimension minus half the original height to centre it.
int newY = (Z / 2) - (Y / 2);
// Draw original bitmap to new location
Paint paint = new Paint();
paint.setAntiAlias(true);
bitmapCanvas.drawBitmap(origBitmap, 0, newY, paint);

Scaled "straight line" image jumps out of line

a have a problem with scaling images up. I have a png file that looks like this:
raw png
The image is 8px * 8px and has some red straight lines on it.
But when i draw this image with java and scale it up this happens: java image
And as you can barly see, the line is not exactly straight. It is always one pixel off and makes this kind of wavy shape. If the image gets drawn somewhere else on the frame the "waves" are somewhere else. The image is rotated 90° but I tested it without rotation and it was still there. Apart from this I do need rotated images.
Is there any way to fix this? I enabled text-antialiasing in the same Graphics2D object. Is there also some sort of anitaliasing for this?
Code
private void loadImage(String path, int field, int imageNumber) {
BufferedImage image;
image = new Resource().readImg(path);
images[field][imageNumber][0] = image;
images[field][imageNumber][1] = rotateClockwise90(image);
images[field][imageNumber][2] = rotateClockwise90(rotateClockwise90(image));
images[field][imageNumber][3] = rotateClockwise90(rotateClockwise90(rotateClockwise90(image)));
}
private BufferedImage rotateClockwise90(BufferedImage src) {
int width = src.getWidth();
int height = src.getHeight();
BufferedImage dest = new BufferedImage(height, width, src.getType());
Graphics2D graphics2D = dest.createGraphics();
graphics2D.translate((height - width) / 2, (height - width) / 2);
graphics2D.rotate(Math.PI / 2, height / 2, width / 2);
graphics2D.drawRenderedImage(src, null);
return dest;
}
When the program starts I load the image I rotate it in all 4 directions, so I don't have to do this over and over again while the program is running.
public BufferedImage getTile(int type, int part, int rotation) {
return images[type][part][rotation];
}
And then all I have to do is calling this get method and draw the image:
g2d.drawImage(tiles.getShipTile(type, part, rotation), x, y, null);

I actually found a way to avoid these weird pixels but this method makes the image a little bit blurry.
Instead of using
g2d.drawImage(img, x, y, width, height, null);
you can simply use
g2d.drawImage(img.getScaledInstance(width, height, Image.SCALE_AREA_AVERAGING), x, y, null);
which does basically the same thing but wehn I scale it up it uses this smooth making key.
I tried this and noticed that its not verry comfortable because it lags a lot.
So I just scale it up in the beginning when I also rotate the images.
As I said this method is a bit blurry but if there are no other ways avoiding this problem I have to get use of this. You almost can't see the blur, so this would be an option for me.

How to rotate a buffered image without cropping it? Is there any way to rotate a JLayeredPane or JLabel?

I had searched about it but I did not get straight forward answer.
I want a buffered image to be rotated but not cropped
I knew the new dimensions are gonna be some thing like this
int w = originalImage.getWidth();
int h = originalImage.getHeight();
double toRad = Math.toRadians(degree);
int hPrime = (int) (w * Math.abs(Math.sin(toRad)) + h * Math.abs(Math.cos(toRad)));
int wPrime = (int) (h * Math.abs(Math.sin(toRad)) + w * Math.abs(Math.cos(toRad)));
Provide me a method for that.
BTW is there any way to rotate a JLabel with an ImageIcon?
Intention: adding to panels and layered pane and also saving it to file (saving the layered pane).
Or can we rotate the layered pane?

How to rotate a buffered image without cropping it?
You had already half of the work by calculating the size of the rotated BufferedImage.
The other half is actually creating the rotated BufferedImage.
You can do that by using Graphics2D
and applying some coordinate transformations before drawing the original image onto the new one. Furthermore, it makes sense to paint the "excess" area with some background color.
public BufferedImage rotateImage(BufferedImage originalImage, double degree) {
int w = originalImage.getWidth();
int h = originalImage.getHeight();
double toRad = Math.toRadians(degree);
int hPrime = (int) (w * Math.abs(Math.sin(toRad)) + h * Math.abs(Math.cos(toRad)));
int wPrime = (int) (h * Math.abs(Math.sin(toRad)) + w * Math.abs(Math.cos(toRad)));
BufferedImage rotatedImage = new BufferedImage(wPrime, hPrime, BufferedImage.TYPE_INT_RGB);
Graphics2D g = rotatedImage.createGraphics();
g.setColor(Color.LIGHT_GRAY);
g.fillRect(0, 0, wPrime, hPrime); // fill entire area
g.translate(wPrime/2, hPrime/2);
g.rotate(toRad);
g.translate(-w/2, -h/2);
g.drawImage(originalImage, 0, 0, null);
g.dispose(); // release used resources before g is garbage-collected
return rotatedImage;
}
Here is a test example from the above code:
Original image
Rotated image (by 30 degree)

BTW is there any way to rotate a JLabel with an ImageIcon?
The easier way is to rotate the Icon, not the label.
Check out Rotated Icon for a class that does the rotation and recalculates the size of the Icon as it is rotated.
Intention: adding to panels and layered pane and also saving it to file (saving the layered pane).
Don't know exactly what that means, but if you just want to save an "image" of the layered pane then check out Screen Image.

Setting up an OpenGL ES renderer for 2D?

I'm trying to set up the renderer so that regardless of device, the view is a simple 2D field with the top of the screen at 1.0f and the bottom at -1.0f. I can't seem to get it quite right, I've been using the below method in the onSurfaceChanged() method and playing with the parameters in gluPerspective to achieve the desired effect, but it seems impossible to make perfect. Surely there is an alternative way to go about this to achieve what i'm after. I've also been playing with the Z values of the meshes drawn to try to get them to match.
Again i'm trying to set it up so that the screen is defined in the range -1.0f to 1.0, so that if you drew a square with sides equal to 2.0f it would fill the entire screen regardless of aspect ratio. What do I need to change to do this? (include the value I should use for the Z dimension of the mesh vertices)
(Don't be alarmed by the strange parameters in gluperspective(), I've been tinkering to see what happens.)
#Override
public void onSurfaceChanged(GL10 gl, int width, int height) {
if(height == 0) { //Prevent A Divide By Zero By
height = 1; //Making Height Equal One
}
gl.glViewport(0, 0, width, height);
gl.glMatrixMode(GL10.GL_PROJECTION);
gl.glLoadIdentity();
GLU.gluPerspective(gl, 90.0f, (float) width / (float) height,
0.0000001f, 100.0f);
gl.glMatrixMode(GL10.GL_MODELVIEW);
gl.glLoadIdentity();
}

Generate a Ortho Matrix instead:
Matrix.orthoM(projectionMatrix,0,-yourdisplayWidth/2,+yourdisplayWidth/2,-yourdisplayHeight/2,+yourdisplayHeight/2,0f,2f);
So you can place your image-quads in distance of 1f in front of your camera. You also have to size your quads as big as they are in pixels. This way you can render pixelperfect.
See also: https://github.com/Chrise55/Llama3D

You might want to try experimenting with using glOrtho or glFrustum instead of glPerspective

How to calculate new height and width for an image to fit with in predefined height and width, without affecting the image real aspect ratio in java?

I want to scale images to fit with in some predefined size without affecting the actual image's aspect ratio.
Do we have any predefined algorithms for that in java?
Update:
Resizing Like this. The output is the same image but in smaller size. The outside frame is just a mark.

you're going to have gaps in either the width or the height... the question is figuring out which.
double widthRatio = realWidth / definedWidth;
double heightRatio = realHeight / definedHeight;
if(heightRatio > widthRatio) {
// scale image to match the height, and let the width have the gaps
} else {
// scale image to match the width, and let the height have the gaps
}