Set Background Image for a Shape drawn by Canvas - android

The goal is to draw some hexagons on the screen and set different background images for those hexagons (I'm making a broad game). I have read about the Shape in XML file, but i want to draw it programmatically. I have drawn a shape with the help of canvas like this:
Path hexPath = hex.getPath();
canvas.clipPath(hexPath);
canvas.drawColor(Color.RED);
how can i set up the background image for this shape ?
I also have read about cropping a Bitmap, but is not practical for me.
Thanks.

Related

create shadow for bitmap in custom view

I have a custom view wich contain some bitmaps and I want to set shadows for them, for that, I use this code:
shadowPaints=new Paint(Paint.ANTI_ALIAS_FLAG);
shadowPaints.setShadowLayer(10.0f, 3.0f, 2.0f, Color.BLACK);
canvas.drawBitmap(bmp, matrix, shadowPaints);
setLayerType(LAYER_TYPE_SOFTWARE, shadowPaints);
and my result is
as you can see my shadow actually is another bitmap with different x and y position but what I want is my shadow be a solid color
bitmap.
can anyone help me about this?
setShadowLayer is actually meant for putting shadows on text.
If you already know the bitmap you want to draw, you can just add a shadow in PhotoShop and draw the bitmap and shadow all at once.
If you don't want to do that, you could make a shadow by making a copy of the image, using a PorterDuff filter to make it all grey, use Renderscript to blur the image, and draw it on the canvas at an x,y offset before drawing the actual image on top of it.
Personally, I think PhotoShop is a lot easier.

how to smooth bitmaps for drawable in android

I create a Bitmap filled-circle with Paint and Canvas and then convert it to a drawable, which I then use as the background to an ImageView. But the image does not look smooth on the phone; the circle has ridges. How do I smooth out the image? I try changing the manifest to say android:hardwareAccelerated="false" and then android:hardwareAccelerated="true" but neither had any effect. I want the image's perimeter to look smooth. The ridges are there whether I use a Stroke or not. I also get the same problem whether I use canvas.drawCircle or canvas.drawOval with RectF

How to draw alpha on an image / setting pixels invisible - on fingertouch

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.

Custom Image View

I have this image that comes back from an API, which represents the users avatar:
However, my graphics department has designed the app to mask the image to make it look like this at runtime (to match our existing design of sharp edges, etc):
Notice the small edge cutout on the bottom left?
I'd love to be able to create a custom ImageView that handled this for me. Unfortunately I'm not sure how to go about doing that. How can I create the bottom image in a custom ImageView. Is this possible? Do I mask it? If so, how?
Thanks!
Using Path and xfer modes to draw on canvas can do the trick. Check this answer how to draw pic to Closed curve area
I think the easiest way to do is to use 2 ImageViews, one with the photo and other above it with a mask for the photo, in your case it would be all transparent except the bottom left to create the cutout with the background color.
You may be able to use android.graphics.Path to draw the complex shape you want. I found this very helpful for a simple custom View, but it seems like you can do a lot with it:
http://developer.android.com/reference/android/graphics/Path.html
Simple code sample for a shaded rectangle:
private Path mRectanglePath;
...
// draw the path
mRectanglePath = new Path();
mRectanglePath.addRect(mLeft, mTop, mRight, mBottom, Path.Direction.CW);
// draw the fill
Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setAlpha(64);
canvas.drawPath(mRectanglePath, paint);

What does 'Paint' parameter do in android.graphics.Canvas.drawBitmap()?

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!

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