I want to roatate an Image with Affinetransform
I did it like this:
AffineTransform at = AffineTransform.getTranslateInstance(image.getWidth(null), image.getHeight(null));
at.rotate(Math.toRadians(getRadian()),image.getWidth(null)/2, image.getHeight(null)/2);
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(image, at, null);
But now I want to set the Position of the Image,how do I do this?
Thanks for help
First of all it's unclear which position of image you want to translate to necessary place. Let me propose general rule. Suppose that you want to be able to rotate image around its internal coordinates (ix,iy) and then place this internal position to new global place with coordinates (gx, gy). And rotation angle is "angleInRadians". Then your transformation will be:
AffineTransform at = AffineTransform.getTranslateInstance(gx, gy);
at.rotate(angleInRadians);
at.translate(-ix, -iy);
Do you see back order of events here? It's because of how transformation matrices are applied to each other and to position vector. If you read this from the end to beginning then what we do is we move internal position to coordinate start, then we rotate around this start and then we move this start to necessary global place.
If you need to move center of image then:
double ix = imageWidth / 2;
double iy = imageHeight / 2;
If you want to move left upper corner then ix = 0 and iy = 0, so you can skip at.translate(-ix, -iy) in this case.
Related
I would like to rotate, scale, and translate a section of an image. For example, I have a sprite-sheet with columns and rows of sprites. I can draw the section I want onto a temporary BufferedImage, then transform that temporary image onto the main graphics, but this is a very slow operation.
How can I make this much much faster? It needs to occur more than 100 * 60 times per second.
public void Draw_WorldSpace(Graphics2D g, double x, double y, double angle, double deltaTime) {
// setup portion of image to transform
BufferedImage tempImage = new BufferedImage(sourceRectangle.width, sourceRectangle.height, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2 = tempImage.createGraphics();
g2.drawImage(image, 0, 0, sourceRectangle.width, sourceRectangle.height, sourceRectangle.x, sourceRectangle.y, sourceRectangle.width, sourceRectangle.height, null);
g2.dispose();
// setup a transformation object
AffineTransform transform = new AffineTransform();
// match view rotation
transform.translate(GameLogic.viewPort.GetCanvasCenter().x, GameLogic.viewPort.GetCanvasCenter().y);
transform.rotate(Math.toRadians(GameLogic.viewPort.GetAngle()));
transform.translate(-GameLogic.viewPort.GetCanvasCenter().x, -GameLogic.viewPort.GetCanvasCenter().y);
// set to position
transform.translate(x - GameLogic.viewPort.GetViewPortCenter().x + GameLogic.viewPort.GetCanvasCenter().x, y - GameLogic.viewPort.GetViewPortCenter().y + GameLogic.viewPort.GetCanvasCenter().y);
// rotate
transform.rotate(Math.toRadians(angle));
// center on sprite
transform.translate(-sourceRectangle.width / 2, -sourceRectangle.height() / 2);
// draw the sprite
g.drawImage(tempImage, transform, null);
}
Ultimately I did what Hovercraft Full Of Eels suggested. I wasn't the biggest fan of the solution simply because it requires a lot of memory overhead. But ultimately, it worked like a charm and even game me more streamlined control over the graphics, so that's really cool.
double degPi = degrees * Math.PI / 180;
double a = Math.cos(degPi)*tImgCover.getScaledHeight();
double b = Math.sin(degPi)*tImgCover.getScaledWidth();
double c = -Math.sin(degPi) * tImgCover.getScaledHeight();
double d = Math.cos(degPi)* tImgCover.getScaledWidth();
double e = absX;
double f = absY;
contentByte.addImage(imgae, a, b, c, d, e, f);/*add image*/
How to rotate around the image center by itext?
If we have an Image image and coordinates x, y, we can draw the image without rotation with its lower left corner at the given coordinates like this
contentByte.addImage(image, image.getWidth(), 0, 0, image.getHeight(), x, y);
A bitmap image from the resources has a size of 1x1 with the coordinate origin at its lower left. Thus, this operation stretches the image to its correct size and moves it so its lower left is at the given coordinates.
If we want to draw the same image as if the one drawn above was rotated around its center by an angle rotate, therefore, we can do this by moving the 1x1 image so that the origin is in its center, stretch it to its correct size, rotate it, and then move the origin (which still is at the center of the rotated image) to the center of the unrotated image. These operations are easier to express using AffineTransform instances (from package com.itextpdf.awt.geom) instead number tupels. Thus:
// Draw image as if the previous image was rotated around its center
// Image starts out being 1x1 with origin in lower left
// Move origin to center of image
AffineTransform A = AffineTransform.getTranslateInstance(-0.5, -0.5);
// Stretch it to its dimensions
AffineTransform B = AffineTransform.getScaleInstance(image.getWidth(), image.getHeight());
// Rotate it
AffineTransform C = AffineTransform.getRotateInstance(rotate);
// Move it to have the same center as above
AffineTransform D = AffineTransform.getTranslateInstance(x + image.getWidth()/2, y + image.getHeight()/2);
// Concatenate
AffineTransform M = (AffineTransform) A.clone();
M.preConcatenate(B);
M.preConcatenate(C);
M.preConcatenate(D);
//Draw
contentByte.addImage(image, M);
(AddRotatedImage.java test method testAddRotatedImage)
For example drawing both images using
int x = 200;
int y = 300;
float rotate = (float) Math.PI / 3;
results in something like this:
With a Flip
The OP asked in a comment
how to add rotate and flip image？
For this you simply insert a mirroring affine transformation into the sequence of transformations above.
Unfortunately the OP did not mention which he meant a horizontal or a vertical flip. But as changing the rotation angle accordingly transforms one in the other, that isn't really necessary, either.
// Draw image as if the previous image was flipped and rotated around its center
// Image starts out being 1x1 with origin in lower left
// Move origin to center of image
AffineTransform A = AffineTransform.getTranslateInstance(-0.5, -0.5);
// Flip it horizontally
AffineTransform B = new AffineTransform(-1, 0, 0, 1, 0, 0);
// Stretch it to its dimensions
AffineTransform C = AffineTransform.getScaleInstance(image.getWidth(), image.getHeight());
// Rotate it
AffineTransform D = AffineTransform.getRotateInstance(rotate);
// Move it to have the same center as above
AffineTransform E = AffineTransform.getTranslateInstance(x + image.getWidth()/2, y + image.getHeight()/2);
// Concatenate
AffineTransform M = (AffineTransform) A.clone();
M.preConcatenate(B);
M.preConcatenate(C);
M.preConcatenate(D);
M.preConcatenate(E);
//Draw
contentByte.addImage(image, M);
(AddRotatedImage.java test method testAddRotatedFlippedImage)
The result with the same image as above:
With Interpolation
The OP asked in a yet another comment
How anti aliasing ?
The iText Image class knows an Interpolation property. By setting it to true (before adding the image to the document, obviously),
image.setInterpolation(true);
low resolution images are subject to interpolation when drawn.
E.g. using a 2x2 image with differently colored pixels instead of the image of Willi, you get the following results, first without interpolation, then with interpolation:
Confer the AddRotatedImage.java test testAddRotatedInterpolatedImage which adds this image:
Beware: iText Image property Interpolation effectively sets the Interpolate entry in the PDF image dictionary. The PDF specification notes in this context:
NOTE A conforming Reader may choose to not implement this feature of PDF, or may use any specific implementation of interpolation that it wishes.
Thus, on some viewers interpolation may occur differently than in your viewer, maybe even not at all. If you need a specific kind of interpolation on every viewer, upscale the image with the desired amount of interpolation / anti-aliasing before loading it into an iText Image.
public static BufferedImage rotateClockwise90( BufferedImage inputImage ){
int width = inputImage.getWidth();
int height = inputImage.getHeight();
BufferedImage returnImage = new BufferedImage( height, width , inputImage.getType() );
for( int x = 0; x < width; x++ ) {
for( int y = 0; y < height; y++ ) {
returnImage.setRGB( height-y-1, x, inputImage.getRGB( x, y ) );
}
}
return returnImage;
}
I'm trying to make a game where the player sometimes have to rotate, but I can't figure out a way to make it rotate more each time, here's what I've got:
Graphics2D g2d = (Graphics2D) g;
AffineTransform at = new AffineTransform();
at.translate(300, Main.height - 115);
if(rotateright) {
at.rotate(Math.PI / 15);
} else if(rotateleft) {
at.rotate(Math.PI / 15);
}
at.scale(0.125, 0.125);
at.translate(-texture.getWidth() / 2, -texture.getHeight() / 2);
g2d.drawImage(texture, at, null);
This method makes it rotate just fine, but I can't find a way to make it rotate more each time, so this method pretty much just rotates it, but only once, and then it just stops. Is there anyway to add to the rotation or something?
you're always starting of with the image in the normal rotation (0 deg/RAD rotated), and then radiating it by PI/15 RAD. if you want it to rotate over time, you will need to multiply PI/15 with a value that will be changing over the duration of your animation.
I have a problem with rotating image in a fixed position with Graphcis2D and AffineTransform.
The idea is to rotate an image according to body's rotation.
The rotation is happening correctly as the rotation angle of the image matches the angle of the body's rotation. However, as the rotation takes place, the image is not drawn to the same position as the body should be drawn. The code of the method painting the picture is the following:
public void paintPicture(Graphics g, Body body) {
Graphics2D g2 = (Graphics2D) g;
Vector2f[] vertices = ((Box) body.getShape()).getPoints(body.getPosition(), body.getRotation());
Vector2f topLeftCorner = vertices[0];
AffineTransform oldTransform = g2.getTransform();
AffineTransform at = new AffineTransform();
at.rotate(body.getRotation());
g2.setTransform(at);
g2.drawImage(this.img, (int) topLeftCorner.x, (int) topLeftCorner.y, null);
g2.setTransform(oldTransform);
}
Any ideas what might cause the movement of the image instead of drawing it according to the coordinates (topLeftCorner.x, topLeftCorner.y)?
You need to first translate you object so the anchor point (the point around which you want it to rotate) is at the origin, perform your rotation, then translate it back. So if you want to rotate around the point (50, 75), you'd do the following:
at.translate (-50, -75);
at.rotate (body.getRotation());
at.translate (50, 75);
I'm assuming that your AffineTransform class can accumulate transformations. If not, you'll need 3 different transforms.
Is there a way to use a Graphics object's 'setClip()' method to clip using a Line-ish shape? Right now I'm trying to use a Polygon shape but I'm having problems simulating the "width" of the line. I basically draw the line, and when I reach the end, I redraw it but this time subtract the line width from y-coordinate:
Polygon poly = new Polygon();
for(int i = 0; i < points.length; i++)
poly.addPoint(points.[i].x, points.[i].y);
// Retrace line to add 'width'
for(int i = points.length - 1; i >=0; i--)
poly.addPoint(points[i].x, points[i].y - lineHeight);
It almost works but the width of the line varies based upon its slope.
I can't use the BrushStroke and drawLine() methods because the line can change color once it passes some arbitrary reference line. Is there some implementation of Shape that I overlooked, or an easy one I can create, that will let me do this more easily?
If there is a better way, I've never run across it. The best I can think of is to use some trigonometry to make the line width more consistent.
OK, I managed to come up with a pretty nice solution without using the setClip() method. It involves drawing my background to an intermediate Graphics2D object, using setComposite() to specify how I want to mask the pixels, THEN drawing my line using drawLine() on top. Once I have this line, I draw it back on top of my original Graphics object via drawImage. Here's an example:
BufferedImage mask = g2d.getDeviceConfiguration().createCompatibleImage(width, height, BufferedImage.TRANSLUCENT);
Graphics2D maskGraphics = (Graphics2D) mask.getGraphics();
maskGraphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
maskGraphics.setStroke(new BasicStroke(lineWidth));
maskGraphics.setPaint(Color.BLACK);
// Draw line onto mask surface first.
Point prev = line.get(0);
for(int i = 1; i < line.size(); i++)
{
Point current = line.get(i);
maskGraphics.drawLine(prev.x, prev.y, current.x, current.y);
prev = current;
}
// AlphaComposite.SrcIn: "If pixels in the source and the destination overlap, only the source pixels
// in the overlapping area are rendered."
maskGraphics.setComposite(AlphaComposite.SrcIn);
maskGraphics.setPaint(top);
maskGraphics.fillRect(0, 0, width, referenceY);
maskGraphics.setPaint(bottom);
maskGraphics.fillRect(0, referenceY, width, height);
g2d.drawImage(mask, null, 0, 0);
maskGraphics.dispose();
Maybe you could use a Stroke.createClippedShape to do this? (May need to use an Area to add subtract the stroked shape from/to your original shape depending on what exactly you are trying to do.