I want to draw a line on the Main Activity using Canvas. The problem is, it is not drawing anything. I have the following code:
Bitmap bitmap = Bitmap.createBitmap(1920, 1080, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.FILL_AND_STROKE);
paint.setStrokeWidth(10);
float left = 20;
float top = 20;
float right = 50;
float bottom = 100;
canvas.drawLine(left, top, right, bottom, paint);
you can display the bitmap like that:
canvas.drawBitmap(bmp, positionX, positionY, paint);
in your case you can try somthing like this:
canvas.drawBitmap(bitmap, 0, 0, null);
but you need to use a diffrent canvas for it. The canvas wich let you draw stuff on your screen will be passed to your onDraw() method in your View. So you need to make a View class first and add it in your MainActivity.
You can do that like this:
First you create a class called MyView and add this code to it:
public class MyView extends View {
Bitmap bitmap;
public MyView(Context context) {
bitmap = Bitmap.createBitmap(1920, 1080, Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.FILL_AND_STROKE);
paint.setStrokeWidth(10);
float left = 20;
float top = 20;
float right = 50;
float bottom = 100;
canvas.drawLine(left, top, right, bottom, paint);
}
#Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(bitmap, 0, 0, null);
super.onDraw(canvas);
}
}
then you change the code in your onCreate() method in your MainActivity to this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
MyView myView = new MyView(this);
setContentView(myView);
}
Create a class like this
public class MyView extends View {
public MyView(Context context) {
super(context);
}
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public MyView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
#Override
protected void onDraw(Canvas canvas) {
Paint paint = new Paint();
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.FILL_AND_STROKE);
paint.setStrokeWidth(10);
float left = 20;
float top = 20;
float right = 50;
float bottom = 100;
canvas.drawLine(left, top, right, bottom, paint);
}
}
Related
Any ideas, code snippets are welcome!
I have created a CustomTextView class that extends AppCompatTextView and I did this to add stroke support to boring TextView. The problem is, Paint.Style.STROKE adds stroke on the inside of TextView. There should be something which allows us to choose between outer-stroke and inner-stroke.
P.S: I can share the complete CustomTextView class if needed, not a big deal.
What we currently have:
What we want to achieve:
This is the onDraw method from our CustomTextView which is used to add stroke to textView.
#Override
protected void onDraw(Canvas canvas) {
if(_strokeWidth > 0) {
//set paint to fill mode
Paint p = getPaint();
p.setStyle(Paint.Style.FILL);
//draw the fill part of text
super.onDraw(canvas);
//save the text color
int currentTextColor = getCurrentTextColor();
//set paint to stroke mode and specify
//stroke color and width
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(_strokeWidth);
setTextColor(_strokeColor);
//draw text stroke
super.onDraw(canvas);
//revert the color back to the one
//initially specified
setTextColor(currentTextColor);
} else {
super.onDraw(canvas);
}
}
The following draws the outline of the characters in a TextView but takes care to clip out the characters themselves so they are not drawn over.
OutlineTextView.java
public class OutlineTextView extends androidx.appcompat.widget.AppCompatTextView {
private final Paint mOutlinePaint = new Paint();
private final Path mOutlinePath = new Path();
private float mStrokeWidth = 0f;
public OutlineTextView(Context context) {
super(context);
init();
}
public OutlineTextView(Context context, #Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
public OutlineTextView(Context context, #Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
mOutlinePaint.setStrokeWidth(0f);
mOutlinePaint.setStyle(Paint.Style.STROKE);
mOutlinePaint.setColor(Color.RED);
}
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
super.onLayout(changed, left, top, right, bottom);
float xOffset = getLayout().getLineLeft(0) + getPaddingLeft();
float baseline = getLayout().getLineBaseline(0) + getPaddingTop();
getPaint().getTextPath(getText().toString(), 0, getText().length(), xOffset, baseline, mOutlinePath);
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mStrokeWidth > 0) {
canvas.save();
// The following insures that we don't draw inside the characters.
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.O) {
canvas.clipPath(mOutlinePath, Region.Op.DIFFERENCE);
} else {
canvas.clipOutPath(mOutlinePath);
}
canvas.drawPath(mOutlinePath, mOutlinePaint);
canvas.restore();
}
}
public void setStrokeWidth(Float strokeWidth) {
mStrokeWidth = strokeWidth;
mOutlinePaint.setStrokeWidth(strokeWidth);
invalidate();
}
}
I want to set corner radius to imageview and control the radius on seekbar. As the seekbar progresses the corner radius should increase and vice-versa.
Currently m getting corner radius on increasing seekbar. But its not setting the imageview to its original state when seek bar is moved back.
cornerRadius.setMax(100);
cornerRadius.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
public void onStopTrackingTouch(SeekBar seekBar) {
}
public void onStartTrackingTouch(SeekBar seekBar) {
}
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
radius= progress;
for (int i = 0; i < IMGS.size(); i++) {
final PhotoView child = IMGS.get(i);
Bitmap viewCapture = null;
child.setDrawingCacheEnabled(true);
viewCapture = Bitmap.createBitmap(child.getDrawingCache());
child.setDrawingCacheEnabled(false);
child.setImageBitmap(getRoundedCornerBitmap(viewCapture,radius));
});
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap, float roundPx) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
Put this class into your java package
public class CustomCornerImageVew extends AppCompatImageView {
private float radius = 20.0f;
private Path path;
private RectF rect;
public CustomCornerImageVew(Context context) {
super(context);
init();
}
public CustomCornerImageVew(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public CustomCornerImageVew(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
path = new Path();
}
#Override
protected void onDraw(Canvas canvas) {
rect = new RectF(0, 0, this.getWidth(), this.getHeight());
path.addRoundRect(rect, radius, radius, Path.Direction.CW);
canvas.clipPath(path);
super.onDraw(canvas);
}
}
And Declare imageview in xml file like this
<YourPackageName.CustomCornerImageVew
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:scaleType="fitXY"
android:src="#drawable/mes" />
you can do by XML like this way
<stroke android:width="3dp"
android:color="#ff000000"/>
<padding android:left="1dp"
android:top="1dp"
android:right="1dp"
android:bottom="1dp"/>
<corners android:radius="30px"/>
and pragmatically you can create rounded bitmap and set in ImageView.
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = 12;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
For Universal lazy loader you can use this wat also.
DisplayImageOptions options = new DisplayImageOptions.Builder()
.displayer(new RoundedBitmapDisplayer(25)) // default
.build();
I am starting with my first attempts to write an android app. I'd like to to visualize the Monte-Carlo-Approximation for pi. Hence I first want to draw a Circle onto a view but i dont get it working!
I have tried to create my own "CircleView" Class which extends "View" and overwrite the onDraw(..) method like its explained over here: How to draw circle by canvas in Android?
This is my CircleView Class
public class CircleView extends View {
public CircleView(Context context) {
super(context);
}
protected void onDraw(Canvas canvas){
super.onDraw(canvas);
Paint paint = new Paint();
paint.setColor(150);
canvas.drawCircle(50,50,20,paint);
}
}
I have inserted the CircleView into a LinearLayout with the following XML-code
<com.tak3r07.montecarlopi.CircleView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/circleView"
android:layout_weight="1"/>
(Btw Android Studio is telling me in the XML-view at the right side: "Rendering Problems Custom view CircleView is not using the 2- or 3-argument View constructors; XML attributes will not work")
The App just crashes with the following log: http://pastebin.com/Gv1GaHtX
Can someone tell what i did wrong?
I thought this setup would create an activity with a view which displays a circle.
Regards
Edit: Crash is fixed by adding the 2 and 3 Parameter Constructor in CircleView (See https://stackoverflow.com/a/13797457/3248708)
But now i still do not see any Circle in the activity
A couple of observations:
You need to take into account the width and height assigned to your view when determining your circle's center point and radius.
You should take into account the padding assigned to your View so you don't draw in that reserved portion.
You should avoid allocating objects within your onDraw method since this gets called a lot.
In order to allow your view to be specified in an XML layout, you need to provide the constructor that takes a Context and an AttributeSet. The AttributeSet is the mechanism by which your XML attributes are passed to your view.
Give this a try:
package com.tak3r07.montecarlopi;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;
public class CircleView extends View
{
private static final int DEFAULT_CIRCLE_COLOR = Color.RED;
private int circleColor = DEFAULT_CIRCLE_COLOR;
private Paint paint;
public CircleView(Context context)
{
super(context);
init(context, null);
}
public CircleView(Context context, AttributeSet attrs)
{
super(context, attrs);
init(context, attrs);
}
private void init(Context context, AttributeSet attrs)
{
paint = new Paint();
paint.setAntiAlias(true);
}
public void setCircleColor(int circleColor)
{
this.circleColor = circleColor;
invalidate();
}
public int getCircleColor()
{
return circleColor;
}
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
int w = getWidth();
int h = getHeight();
int pl = getPaddingLeft();
int pr = getPaddingRight();
int pt = getPaddingTop();
int pb = getPaddingBottom();
int usableWidth = w - (pl + pr);
int usableHeight = h - (pt + pb);
int radius = Math.min(usableWidth, usableHeight) / 2;
int cx = pl + (usableWidth / 2);
int cy = pt + (usableHeight / 2);
paint.setColor(circleColor);
canvas.drawCircle(cx, cy, radius, paint);
}
}
You can create a Circular layout and inside this view, every childs should be rounded up :
public class CircleView extends FrameLayout {
private Bitmap maskBitmap;
private Paint paint, maskPaint;
public CircleView(Context context) {
super(context);
init();
}
public CircleView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public CircleView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
#RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)
public CircleView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
super(context, attrs, defStyleAttr, defStyleRes);
init();
}
private void init() {
paint = new Paint(Paint.ANTI_ALIAS_FLAG);
maskPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.FILTER_BITMAP_FLAG);
maskPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
setWillNotDraw(false);
}
#Override
public void draw(Canvas canvas) {
Bitmap offscreenBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas offscreenCanvas = new Canvas(offscreenBitmap);
super.draw(offscreenCanvas);
if (maskBitmap == null) {
maskBitmap = createMask(getWidth(), getHeight());
}
offscreenCanvas.drawBitmap(maskBitmap, 0f, 0f, maskPaint);
canvas.drawBitmap(offscreenBitmap, 0f, 0f, paint);
}
private Bitmap createMask(int width, int height) {
Bitmap mask = Bitmap.createBitmap(width, height, Bitmap.Config.ALPHA_8);
Canvas canvas = new Canvas(mask);
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.WHITE);
canvas.drawRect(0, 0, width, height, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
canvas.drawRoundRect(new RectF(0, 0, width, height), width/2f, height/2f, paint);
return mask;
}
}
I want to draw circle by canvas. Here is my code:
[MyActivity.java]:
public class MyActivity extends Activity
{
public void onCreate(Bundle savedInstanceState)
{
...
setContentView(new View(this,w,h));
}
}
[View.java]:
public class View extends SurfaceView
{
public View(Context context, int w, int h)
{
super(context);
Canvas grid = new Canvas(Bitmap.createBitmap(h,w, Bitmap.Config.ARGB_8888));
grid. drawColor(Color.WHITE);
Paint paint = new Paint();
paint.setStyle(Paint.Style.FILL);
grid.drawCircle(w/2, h/2 , w/2, paint);
}
}
So I have just black screen without circle.
Why it does not work? How to fix it?
You can override the onDraw method of your view and draw the circle.
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawCircle(x, y, radius, paint);
}
For a better reference on drawing custom views check out the official Android documentation.
http://developer.android.com/training/custom-views/custom-drawing.html
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
public class MainActivity extends Activity
{
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(new MyView(this));
}
public class MyView extends View
{
Paint paint = null;
public MyView(Context context)
{
super(context);
paint = new Paint();
}
#Override
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
int x = getWidth();
int y = getHeight();
int radius;
radius = 100;
paint.setStyle(Paint.Style.FILL);
paint.setColor(Color.WHITE);
canvas.drawPaint(paint);
// Use Color.parseColor to define HTML colors
paint.setColor(Color.parseColor("#CD5C5C"));
canvas.drawCircle(x / 2, y / 2, radius, paint);
}
}
}
Edit
if you want to draw circle at centre. You could also translate your entire canvas to center then draw circle at center.using
canvas.translate(getWidth()/2f,getHeight()/2f);
canvas.drawCircle(0,0, radius, paint);
These two link also help
http://www.compiletimeerror.com/2013/09/introduction-to-2d-drawing-in-android.html#.VIg_A5SSy9o
http://android-coding.blogspot.com/2012/04/draw-circle-on-canvas-canvasdrawcirclet.html
public class CircleView extends View {
private static final String COLOR_HEX = "#E74300";
private final Paint drawPaint;
private float size;
public CircleView(final Context context, final AttributeSet attrs) {
super(context, attrs);
drawPaint = new Paint();
drawPaint.setColor(Color.parseColor(COLOR_HEX));
drawPaint.setAntiAlias(true);
setOnMeasureCallback();
}
#Override
protected void onDraw(final Canvas canvas) {
super.onDraw(canvas);
canvas.drawCircle(size, size, size, drawPaint);
}
private void setOnMeasureCallback() {
ViewTreeObserver vto = getViewTreeObserver();
vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
#Override
public void onGlobalLayout() {
removeOnGlobalLayoutListener(this);
size = getMeasuredWidth() / 2;
}
});
}
#TargetApi(Build.VERSION_CODES.JELLY_BEAN)
private void removeOnGlobalLayoutListener(ViewTreeObserver.OnGlobalLayoutListener listener) {
if (Build.VERSION.SDK_INT < 16) {
getViewTreeObserver().removeGlobalOnLayoutListener(listener);
} else {
getViewTreeObserver().removeOnGlobalLayoutListener(listener);
}
}
}
Xml example: will produce a circle of 5dp
<com.example.CircleView
android:layout_width="10dp"
android:layout_height="10dp"/>
If you are using your own CustomView extending View class, you need to call canvas.invalidate() method which will internally call onDraw method. You can use default API for canvas to draw a circle. The x, y cordinate define the center of the circle. You can also define color and styling in paint & pass the paint object.
public class CustomView extends View {
public CustomView(Context context, AttributeSet attrs) {
super(context, attrs);
setupPaint();
}
}
Define default paint settings and canvas (Initialise paint in constructor so that you can reuse the same object everywhere and change only specific settings wherever required)
private Paint drawPaint;
// Setup paint with color and stroke styles
private void setupPaint() {
drawPaint = new Paint();
drawPaint.setColor(Color.BLUE);
drawPaint.setAntiAlias(true);
drawPaint.setStrokeWidth(5);
drawPaint.setStyle(Paint.Style.FILL_AND_STROKE);
drawPaint.setStrokeJoin(Paint.Join.ROUND);
drawPaint.setStrokeCap(Paint.Cap.ROUND);
}
And initialise canvas object
private Canvas canvas;
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
this.canvas = canvas;
canvas.drawCircle(xCordinate, yCordinate, RADIUS, drawPaint);
}
And finally, for every view refresh or new draw on the screen, you need to call invalidate method. Remember your entire view is redrawn, hence this is an expensive call. Make sure you do only the necessary operations in onDraw
canvas.invalidate();
For more details on canvas drawing refer https://medium.com/#mayuri.k18/android-canvas-for-drawing-and-custom-views-e1a3e90d468b
#Override
public void onDraw(Canvas canvas){
canvas.drawCircle(xPos, yPos,radius, paint);
}
Above is the code to render a circle. Tweak the parameters to your suiting.
Try this
The entire code for drawing a circle or download project source code and test it on your android studio. Draw circle on canvas programmatically.
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.graphics.PorterDuff;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.widget.ImageView;
public class Shape {
private Bitmap bmp;
private ImageView img;
public Shape(Bitmap bmp, ImageView img) {
this.bmp=bmp;
this.img=img;
onDraw();
}
private void onDraw(){
Canvas canvas=new Canvas();
if (bmp.getWidth() == 0 || bmp.getHeight() == 0) {
return;
}
int w = bmp.getWidth(), h = bmp.getHeight();
Bitmap roundBitmap = getRoundedCroppedBitmap(bmp, w);
img.setImageBitmap(roundBitmap);
}
public static Bitmap getRoundedCroppedBitmap(Bitmap bitmap, int radius) {
Bitmap finalBitmap;
if (bitmap.getWidth() != radius || bitmap.getHeight() != radius)
finalBitmap = Bitmap.createScaledBitmap(bitmap, radius, radius,
false);
else
finalBitmap = bitmap;
Bitmap output = Bitmap.createBitmap(finalBitmap.getWidth(),
finalBitmap.getHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, finalBitmap.getWidth(),
finalBitmap.getHeight());
paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(Color.parseColor("#BAB399"));
canvas.drawCircle(finalBitmap.getWidth() / 2 + 0.7f, finalBitmap.getHeight() / 2 + 0.7f, finalBitmap.getWidth() / 2 + 0.1f, paint);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_IN));
canvas.drawBitmap(finalBitmap, rect, rect, paint);
return output;
}
Here is example to draw stroke circle canvas
val paint = Paint().apply {
color = Color.RED
style = Paint.Style.STROKE
strokeWidth = 10f
}
override fun onDraw(canvas: Canvas?) {
super.onDraw(canvas)
canvas?.drawCircle(200f, 100f, 100f, paint)
}
Result
Example to draw solid circle canvas
val paint = Paint().apply {
color = Color.RED
}
override fun onDraw(canvas: Canvas?) {
super.onDraw(canvas)
canvas?.drawCircle(200f, 100f, 100f, paint)
}
Result
Hope it help
private Paint green = new Paint();
private int greenx , greeny;
green.setColor(Color.GREEN);
green.setAntiAlias(false);
canvas.drawCircle(greenx,greeny,20,green);
I would like to change an image I loaded to have round corners.
Any hints, tutorials, best practices you know of?
For a more controlled method draw a rounded rectangle and mask it onto your image using the porter-duff Xfer mode of the paint.
First setup the Xfer paint and the rounded bitmap:
Bitmap myCoolBitmap = ... ; // <-- Your bitmap you want rounded
int w = myCoolBitmap.getWidth(), h = myCoolBitmap.getHeight();
// We have to make sure our rounded corners have an alpha channel in most cases
Bitmap rounder = Bitmap.createBitmap(w,h,Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(rounder);
// We're going to apply this paint eventually using a porter-duff xfer mode.
// This will allow us to only overwrite certain pixels. RED is arbitrary. This
// could be any color that was fully opaque (alpha = 255)
Paint xferPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
xferPaint.setColor(Color.RED);
// We're just reusing xferPaint to paint a normal looking rounded box, the 20.f
// is the amount we're rounding by.
canvas.drawRoundRect(new RectF(0,0,w,h), 20.0f, 20.0f, xferPaint);
// Now we apply the 'magic sauce' to the paint
xferPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
Now apply this bitmap ontop of your image:
Bitmap result = Bitmap.createBitmap(myCoolBitmap.getWidth(), myCoolBitmap.getHeight() ,Bitmap.Config.ARGB_8888);
Canvas resultCanvas = new Canvas(result)
resultCanvas.drawBitmap(myCoolBitmap, 0, 0, null);
resultCanvas.drawBitmap(rounder, 0, 0, xferPaint);
Bitmap with rounded corners now resides in result.
Why not use clipPath?
protected void onDraw(Canvas canvas) {
Path clipPath = new Path();
float radius = 10.0f;
float padding = radius / 2;
int w = this.getWidth();
int h = this.getHeight();
clipPath.addRoundRect(new RectF(padding, padding, w - padding, h - padding), radius, radius, Path.Direction.CW);
canvas.clipPath(clipPath);
super.onDraw(canvas);
}
Romain Guy himself writes about this in his blog:
To generate the rounded images I simply wrote a custom Drawable that
draws a rounded rectangle using Canvas.drawRoundRect(). The trick is
to use a Paint with a BitmapShader to fill the rounded rectangle with
a texture instead of a simple color. Here is what the code looks like:
BitmapShader shader;
shader = new BitmapShader(bitmap, Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setShader(shader);
RectF rect = new RectF(0.0f, 0.0f, width, height);
// rect contains the bounds of the shape
// radius is the radius in pixels of the rounded corners
// paint contains the shader that will texture the shape
canvas.drawRoundRect(rect, radius, radius, paint);
The sample application goes a little further and fakes a vignette
effect by combining the BitmapShader with a RadialGradient.
Here's a way I discovered to do it with an ImageView. I tried other methods, including the answers here and on similar questions, but I found that they didn't work well for me, as I needed the corners to be applied to the image view and not directly to the bitmap. Applying directly to the bitmap won't work if you're scaling/cropping/panning that bitmap, since the corners will also be scaled/cropped/panned.
public class RoundedCornersImageView extends ImageView {
private final Paint restorePaint = new Paint();
private final Paint maskXferPaint = new Paint();
private final Paint canvasPaint = new Paint();
private final Rect bounds = new Rect();
private final RectF boundsf = new RectF();
public RoundedCornersImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
public RoundedCornersImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public RoundedCornersImageView(Context context) {
super(context);
init();
}
private void init() {
canvasPaint.setAntiAlias(true);
canvasPaint.setColor(Color.argb(255, 255, 255, 255));
restorePaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));
maskXferPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY));
}
#Override
protected void onDraw(Canvas canvas) {
canvas.getClipBounds(bounds);
boundsf.set(bounds);
canvas.saveLayer(boundsf, restorePaint, Canvas.ALL_SAVE_FLAG);
super.onDraw(canvas);
canvas.saveLayer(boundsf, maskXferPaint, Canvas.ALL_SAVE_FLAG);
canvas.drawARGB(0, 0, 0, 0);
canvas.drawRoundRect(boundsf, 75, 75, canvasPaint);
canvas.restore();
canvas.restore();
}
}
Here's an alternative that uses hardware layers for the final layer composite:
public class RoundedCornersImageView extends ImageView {
private final Paint restorePaint = new Paint();
private final Paint maskXferPaint = new Paint();
private final Paint canvasPaint = new Paint();
private final Rect bounds = new Rect();
private final RectF boundsf = new RectF();
public RoundedCornersImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
public RoundedCornersImageView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public RoundedCornersImageView(Context context) {
super(context);
init();
}
private void init() {
canvasPaint.setAntiAlias(true);
canvasPaint.setColor(Color.argb(255, 255, 255, 255));
restorePaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP));
maskXferPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY));
setLayerType(View.LAYER_TYPE_HARDWARE, restorePaint);
}
#Override
protected void onDraw(Canvas canvas) {
canvas.getClipBounds(bounds);
boundsf.set(bounds);
super.onDraw(canvas);
canvas.saveLayer(boundsf, maskXferPaint, Canvas.ALL_SAVE_FLAG);
canvas.drawARGB(0, 0, 0, 0);
canvas.drawRoundRect(boundsf, 75, 75, canvasPaint);
canvas.restore();
}
}
At first I wasn't able to get it to work with this method because my corners were becoming black; I later realized what the problem was after reading this question: Android how to apply mask on ImageView?. It turns out that modifying the alpha in the canvas is actually "scratching it out" directly on the screen, and punching a hole to the underlying window which is black. That's why two layers are needed: one to apply the mask, and another to apply the composited image to the screen.
How about creating a NinePatchDrawable image that has just rounded corners and has a transparent body. Overlay your image with an appropriately re-sized version of your NinePatchDrawable.
package com.pkg;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.PorterDuffXfermode;
import android.graphics.Rect;
import android.graphics.RectF;
import android.graphics.Bitmap.Config;
import android.graphics.PorterDuff.Mode;
import android.os.Bundle;
import android.os.Environment;
import android.widget.ImageView;
public class RoundedImage extends Activity {
/** Called when the activity is first created. */
ImageView imag;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
imag=(ImageView)findViewById(R.id.image);
//ImageView img1=(ImageView)findViewById(R.id.imageView1);
BitmapFactory.Options bitopt=new BitmapFactory.Options();
bitopt.inSampleSize=1;
// String img=Environment.getExternalStorageDirectory().toString();
// String filepath =Environment.getExternalStorageDirectory().toString();
String filepath ="/mnt/sdcard/LOST.DIR";
File imagefile = new File(filepath + "/logo.jpg");
FileInputStream fis = null;
try
{
fis = new FileInputStream(imagefile);
}
catch (FileNotFoundException e1)
{
// TODO Auto-generated catch block
e1.printStackTrace();
}
Bitmap bi = BitmapFactory.decodeStream(fis);
if(bi!=null){
imag.setImageBitmap(getRoundedCornerBitmap(bi));
}
}
public static Bitmap getRoundedCornerBitmap(Bitmap bitmap) {
Bitmap output = Bitmap.createBitmap(bitmap.getWidth(),
bitmap.getHeight(), Config.ARGB_8888);
Canvas canvas = new Canvas(output);
final int color = 0xff424242;
final Paint paint = new Paint();
final Rect rect = new Rect(0, 0, bitmap.getWidth(), bitmap.getHeight());
final RectF rectF = new RectF(rect);
final float roundPx = 12;
paint.setAntiAlias(true);
canvas.drawARGB(0, 0, 0, 0);
paint.setColor(color);
canvas.drawRoundRect(rectF, roundPx, roundPx, paint);
paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
canvas.drawBitmap(bitmap, rect, rect, paint);
return output;
}
}
Here's another rounded ImageView implementation using Path. The performance is great, but in certain conditions some bugs may appear on emulators because of the hardware drawing.
public class RoundImageView extends ImageView {
private Path mPath;
private RectF mRect;
private Paint mPaint;
private int mCornerRadius;
private float mImageAlpha;
private boolean mIsCircular;
public RoundImageView(Context context) {
this(context, null);
}
public RoundImageView(Context context, AttributeSet attrs) {
this(context, attrs, R.attr.roundImageViewStyle);
}
public RoundImageView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
TypedArray a = context.obtainStyledAttributes(
attrs, R.styleable.RoundImageView, defStyle, 0);
mCornerRadius = a.getDimensionPixelSize(R.styleable.RoundImageView_cornerRadius, 0);
mIsCircular = a.getBoolean(R.styleable.RoundImageView_isCircular, false);
mImageAlpha = a.getFloat(R.styleable.RoundImageView_imageAlpha, 1);
a.recycle();
setAlpha((int) (mImageAlpha * 255));
// Avoid expensive off-screen drawing
setLayerType(LAYER_TYPE_HARDWARE, null);
mPath = new Path();
mRect = new RectF();
mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));
}
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
mPath.reset();
if (mIsCircular) {
float halfWidth = canvas.getWidth() / 2;
float halfHeight = canvas.getHeight() / 2;
float radius = Math.max(halfWidth, halfHeight);
mPath.addCircle(halfWidth, halfHeight, radius, Path.Direction.CW);
} else {
mRect.right = canvas.getWidth();
mRect.bottom = canvas.getHeight();
mPath.addRoundRect(mRect, mCornerRadius, mCornerRadius, Path.Direction.CW);
}
canvas.drawPath(mPath, mPaint);
}
}
P.S. Learn OpenGL ES provided the best solution. It's very smooth and works on emulators too.
best solution I found ->
1) create rounded corner drawable. And set to imageview as background.
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<corners
android:radius="10dp" /></shape>
2) Then set image view object property of setClipToOutline(true) in java code.
imageview.setClipToOutline(true);
It works like charm