I'm trying to do an app in Android that work with finger paint and that must be able to manage the zoom. So I have an image in the background and I draw over it, but when I zoom in and out, I have to resize both the image and the path drawn and I don't know how. I used the code of Zdnet to implement the pinch to zoom gesture and it works great for the background image, so I thought that the only step to make the "path resize" was to put mPath.transform(matrix) at the end of onTouch(), but it doesn't allow me to draw properly and does not resize the path.
How could I do it?
Note: the code to implement the finger paint is that of Google.
mPath.transform should work, it's hard to tell what's wrong without code.
Alternatively, you could use Canvas.scale if you want to scale everything drawn by the same factor.
Related
I'm struggling with something I would expect to be straight forward with libgdx.
In short this is a "finger paint" app where I want to draw a path of a certain width where the user touches the screen.
I've earlier done this by using a plain Android android.view.View. I had a android.graphics.Path in which I stored the coordinates of the user's current touch. In the onDraw() method of the view I drew the path to the android.graphics.Canvas. Whenever the user released a finger I drew the path to an offline canvas/android.graphics.Bitmap which also was drawn in the onDraw() method. Plain and simple.
How can that be done using libgdx?
I have tried using a com.badlogic.gdx.graphics.Pixmap that I can draw a line to whenever the user moves a finger. This works well except the fact that I'm unable to control the witdh of the line using Gdx.gl.glLineWidth(). I know I can draw a rectangle instead of a line to set the width, but Pixmap doesn't seem to have any means of rotating, so I don't see how this can be done.
I can use a com.badlogic.gdx.graphics.glutils.ShapeRenderer for drawing lines (or rectangles) in com.badlogic.gdx.Screen.render(). As far as I can see I then need to store every single touch point of the current touch, and then draw all lines on render. Whenever the user relases a finger I guess I can store the screen as-is with something like com.badlogic.gdx.utils.ScreenUtils.getFrameBufferPixmap(). Hopefully there is a easier way to achieve what I want.
I ended up drawing circles on a pixmap where the line should be:
One circle on touchDown
Several circles from last touch point to next touch point reported to touchDragged
I'm not very happy with this solution, but it kinda works.
Maybe you can calculate line dot coordinates manually and use triangles to draw them on pixmap? Like use 2 triangles to form (rotated) box?
I am using the Multitouch Controller made by Luke Hutchison found here
https://code.google.com/p/android-multitouch-controller/
My problem is this. I can place an image onto the canvas. I can select it, move it, rotate it and scale it perfectly fine. The problem is I also allow the user to move the canvas by translating it on drag. On the screen the images seem to appear in the correct location following the translation of the entire canvas. The problem is trying to select them afterwards.
I don't know if it's an issue with the touch point after the canvas translation not taking into account the new canvas location/offset or the location of the images haven't been updated with the canvas translation. Does anyone have any experience with this or be able to point me in the right direction!?
I'm new to Android (and Java for that matter), and I'm making a simple game. I'm stuck.
My problem is this:
I have 2 png images (a background and foreground) that take up the whole screen on startup. I now want to be able to set the width of the "drawn portion" of the foreground to the x-coordinate of ON_DRAG. My control method works fine; it's used like this:
g.drawRect(0, 0, scene.getLine(), g.getHeight(), Color.GREEN);
where scene.getLine() returns the x-value of the touch. So at this point I can draw a green rectangle above my images. But what I actually want is for those rectangle dimensions to "punch a hole" in my top-layer png (so the background is revealed beneath). I do not want to scale the foreground.
I have tried clipRect, but it doesnt work because I have other images that need to be drawn on top of these two, and clipRect prevents this. I have looked at a bunch of "PorterDuffXfermode" code, but cannot understand how to apply it to my situation, and cannot make it work. i.e. I can make a Paint with the PorterDuff "SRC" mode set, but I dont know how to define "source" and "destination" images so the Paint will work its magic. A final consideration with this is that even if the PorterDuff would work, Im not sure it would be practical given that I want this thing to run at 60fps.
Any suggestions?
Thanks.
You can call canvas.save() before a clip and canvas.restore() after your drawing to return the canvas to the sate it was in before you stared. Then you can draw your additional images.
I am developing one application with drawing and all, One problem I am facing is I want single touch scaling image. I have done image scaling with multi touch but I am so stuck with single touch.
Example :-
I have one Rectangle on canvas. Now I want to scale and rotate that Rectangle with its one corner with one finger. I am finding this on google but not get perfect materiel or demo and else.
Please help me to find this.
For zooming with single touch this will help you
http://developer.sonymobile.com/wp/2010/05/18/android-one-finger-zoom-tutorial-part-1/
in my application I want to have a frame (with a hole in the middle) and an image under it. I want to be able to drag and zoom the image to fit (the face in the picture) it in the frame. Then Crop the image (could I find the pixel x,y that are in the border of the screen?) and then save the zoomed image so that I can put the frame over it then.
Any suggestions? If possible please tell me the classes I will have to use.
Thanks!!
It is possible to do all the functionalities (What you have discussed above) using Android View class with onDraw method and canvas Object.
Refer the link:
http://developer.android.com/reference/android/graphics/Canvas.html