Canvas for Android Game Development

Get the canvas object
[Java]
Canvas canvas = getHolder (). lockCanvas ();

Canvas attributes, methods, and applications
[Java]
If (canvas! = Null ){
// ---- Set the canvas drawing to be non-sawtooth
Canvas. setDrawFilter (pfd );
// ---- Use the canvas to fill the screen
Canvas. drawColor (Color. BLACK );
// ---- Draw text
Canvas. drawText ("drawText", 10, 10, paint );
// ---- Draw the pixel
Canvas. drawPoint (10, 20, paint );
// ---- Draw multiple pixels
Canvas. drawPoints (new float [] {10, 30, 30, 30}, paint );
// ---- Draw a straight line
Canvas. drawLine (10, 40, 50, 40, paint );
// ---- Draw multiple straight lines
Canvas. drawLines (new float [] {10, 50, 50, 50, 70, 50,110, 50}, paint );
// ---- Draw a rectangle
Canvas. drawRect (10, 60, 40,100, paint );
// ---- Draw a rectangle 2
Rect rect = new Rect (10,110, 60,130 );
Canvas. drawRect (rect, paint );
Canvas. drawRect (rect, paint );
// ---- Draw a rounded rectangle
RectF rectF = new RectF (10,140, 60,170 );
Canvas. drawRoundRect (rectF, 20, 20, paint );
// ---- Draw a circle
Canvas. drawCircle (20,200, 20, paint );
// ---- Draw an arc
Canvas. drawArc (new RectF (150, 20,200, 70), 0,230, true, paint );
// ---- Draw an ellipse
Canvas. drawOval (new RectF (150, 80,180,100), paint );
// ---- Draw the specified path Image
Path path = new Path ();
// Set the path start point
Path. moveTo (160,150 );
// Route 1
Path. lineTo (200,150 );
// Route 2
Path. lineTo (180,200 );
// The path ends.
Path. close ();
Canvas. drawPath (path, paint );
// ---- Draw the specified path Image
Path pathCircle = new Path ();
// Add a circular path
PathCircle. addCircle (130,260, 20, Path. Direction. CCW );
// ---- Draw the path text with a circle
Canvas. drawTextOnPath ("PathText", pathCircle, 10, 20, paint );
}
 
NOTE: For the above Code, refer to "programming for Android games from scratch".

Get the bitmap with the width of the custom image (parameter 1: context object, parameter 2: Resource ID, parameter 3: Custom width, parameter 4: Custom height)
[Java]
Public static Bitmap loadBallView (Context context, int resId, int width, int height ){

Resources resources = context. getResources ();

Drawable image = resources. getDrawable (resId );

Bitmap bitmap = Bitmap. createBitmap (width, height, Bitmap. Config. ARGB_8888 );

Canvas canvas = new Canvas (bitmap );
Image. setBounds (0, 0, width, height );
Image. draw (canvas );

Return bitmap;
}
 
Use canvas to draw bitmap
[Java]
Bitmap bitmap = loadBallView (context, R. drawable. image, 100,100 );
 
Paint paint = new Paint ();
 
Canvas. drawBitmap (bitmap, startX, startY, paint); // parameter 1: bitmap resource, parameter 2: Start X coordinate, parameter 3: Start Y coordinate, parameter 4: paint object