I have an 8x8 Image. (bitmap - can be changed)
What I want to do is be able to draw a shape, given a Path and Paint object onto my SurfaceView.
At the moment all I can do is fill the shape with solid colour. How can I draw it with a pattern.
In the image you can see the brush pattern (The cross). It can be anything from a cross to a donut or an elf.
How would I go about drawing this pattern background.
I also eventually want to apply colours to it.
So far, my theory is to create a clip area of the shape, and tile the bitmaps until area is covered, but this is extreme overkill in processing. Nor sound ideal.
In terms of colouring, I can edit the brushes to be alpha, fill the same with background colour, then draw the images on top. The real issue it the tiling of such patterns.
Ive found a few questions of a similar nature, all unanswered, and/or not applicable to my situation. (use of xmls on views etc)
Did you checked this blog. Its using BitmapShader
Example:
//Initialize the bitmap object by loading an image from the resources folder
fillBMP = BitmapFactory.decodeResource(m_context.getResources(), R.drawable.cross);
//Initialize the BitmapShader with the Bitmap object and set the texture tile mode
fillBMPshader = new BitmapShader(fillBMP, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
fillPaint.setStyle(Paint.Style.FILL);
//Assign the 'fillBMPshader' to this paint
fillPaint.setShader(fillBMPshader);
//Draw the fill of any shape you want, using the paint object.
canvas.drawCircle(posX, posY, 100, fillPaint);
Related
Imagine that I have a rectangle image. How could I create a style like the next one?
I mean, cropping the image into a circle, add the border, the shadow and the gross /shine effect. Until now, I only have tried this snippet code to crop the image: Cropping circular area from bitmap in Android but just that. I have no idea how to do the remaining components in Android.
An easy way to achieve this effect is to use Canvas.drawCircle() and a BitmapShader:
BitmapShader s = new BitmapShader(myPhoto, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
Paint p = new Paint();
p.setShader(s);
myCanvas.drawCircle(centerX, centerY, radius, p);
To do the shadow, simply call Paint.setShadowLayer() on the paint (this will only work if you draw the effect into an offscreen Bitmap or if your View uses a software layer – set by calling View.setLayerType() –).
The border can be drawn by drawing another circle on top, using the Paint.Style.STROKE style (that you can set by calling Paint.setStyle()).
Finally you can draw the gloss by drawing a circle, oval or Path on top of your very first circle. You'll need to use a LinearGradient shader on your paint and you'll also need to clip the gloss. You can do this in two ways:
If you are drawing the entire effect into a Bitmap, which is what I would recommend, simply set the paint's Xfermode to a new PorterDuffXfermode(PorterDuff.Mode.SRC_IN).
If you are drawing the effect directly on screen you can simply use Canvas.clipPath() to set a circular clip. Note that this will work with hardware acceleration only as of Android 4.3.
I want to make in my app possibilty to draw circles by user. The drawing is quite simple - user just press on canvas somewhere and then predefined circle
The difficult part here is to draw it with some drawable (picture) as a fill. It is quite simple when it is about rectangle. Then you just need to write:
Drawable drawable = getResources().getDrawable(R.drawable.my_background_picture);
drawable.setBounds(myRectangle);
drawable.draw(myCanvas);
Everything is done on onDraw() method of my custom view.
Unfortunatelly there isn't such simple method to make it with circle. The one that I've found is slight modification from Vogella's tutorial:
InputStream resource = getResources().openRawResource(R.drawable.sand);
Bitmap bitmap = BitmapFactory.decodeStream(resource);
BitmapShader shader;
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP,Shader.TileMode.CLAMP);
paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(shader);
myCanvas.drawRoundRect(myRectangle, 120, 120, paint);
At first sight it looks ok, but it's not. This commands make just something like frame on a picture below, so you move hollow circle on a picture and that's all. Not as with rectangle where you actually move rectangular bitmap.
So, my question is - Is there a way to make circle drawable that can be also moved/resized?
Why make a drawable? You can easily draw a circle via the canvas.drawCircle command. You can also easily make one via a Path object.
Edit:
If you need a drawable, try making a ShapeDrawable based off an OvalShape.
I want to create a little scratch game. The problem is, that I can't figure out how to erase pixels from an image in android (like the eraser in gimp / photoshop).
The image is an .png with alpha channel.
AIUI, drawing operations on a canvas blend a transparent pixel with the prior value of the pixel. This is by default, and you can see it by setting a canvas to black and drawing a fully transparent shape onto it, and then drawing the underlying bitmap over an image of another canvas (result: a fully black canvas), or by setting a canvas to a partially transparent color and, drawing a shape of another partially transparent color, and then drawing this over an image (result: the original image is tinted by the first color, outside the shape; within the shape, it's tinted by both transparent colors). I don't know the blending method used by default, and looking through the docs just makes me wish I knew what book to buy so I can understand how to use what's available.
So I would set pixels to transparent by setting them 'directly', with Bitmap methods, rather than with canvas operations. Although if you need to punch a transparent shape into an overlay, you can draw the shape with a solid non-transparent color, and then manipulate the bitmap directly, mapping this color to the transparent color.
Bitmap docs. Prefer getPixels() and setPixels() to a method-call per pixel.
EDIT: ...er, did I misunderstand? You want to 'erase' pixels as in a paint program? Then just draw whatever the background color is. There's no erasure involved.
I have a question about drawBitmap.
android.graphics.Canvas.drawBitmap(Bitmap bitmap, float left, float top, Paint paint)
What does that Paint paint? For example I have a picture.jpg and I make
Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.picture);
paint = new Paint();
paint.setColor(Color.BLUE);
canvas.drawBitmap(bitmap, 0, 0, paint);
What can I do with that "paint" when I have a real picture not some canvas.drawCircle. Is there any way I can change pictures color or something like that?
Yes and another question. For example I draw circle in mspaint in 80x80 size and my background stays plain white. When I use that drawing in my program it shows circle + that white background. Is there any way that there will be displayed only circle without background. Maybe somebody can suggest some program in which I can make that happen or which code should I use in my program? (circle is just example, there can be anything)
Yes and excuse to use circle's background same as program's background is not appropriate, because my program's background isn't white or black or any other color, it is picture.
Paint objects can affect the rendering of the Bitmap. For example, they be used to mask the drawing of the Bitmap.
Save your circle as a PNG or GIF, and set the background as transparent (I do not know if MS Paint can do this).
i suggest gimp for image editing with transparency.
start a new image, delete the default layer, add a transparent layer, then paste your image over that. you can use the fuzzy select tool to trim any white space, then save as .png and you have a transparent image!
I have several bitmaps (game sprites) which I'd like to draw into another bitmap, however each non-transparent pixel of the source bitmap should be drawn using a single color, ignoring the original pixel color of the source. Basically, I'm trying to use the sprite as a "stamp" of a single color to be drawn into the destination bitmap.
I believe I should be using canvas.drawBitmap (Bitmap bitmap, Matrix matrix, Paint paint), however I'm not exactly sure how I should initialize the paint object. Is this approach correct?
You don't need to perform as many steps as Romain Guy suggests, just initialize your paint with the desired color, and use Paint.setColorFilter() with PorterDuff.Mode.SRC_ATOP
myPaint.setColorFilter(new PorterDuffColorFilter(myColor, PorterDuff.Mode.SRC_ATOP));
If your destination bitmap is transparent, draw all your sprites inside that bitmap normally (you can use a null Paint.) Then, draw a filled rectangle that covers the entire bitmap, using the Porter-Duff xfermode called SrcIn (Source In.)