英文:
android - Canvas draw path on canvas without touch direction
问题
以下是翻译好的代码部分:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.MotionEvent;
import androidx.appcompat.widget.AppCompatImageView;
public class RachetBasic extends AppCompatImageView {
private Canvas canvas;
private Bitmap bitmap;
private Paint bitmapPaint = new Paint(Paint.DITHER_FLAG);
private Path squarePath = new Path();
private Paint squarePaint = new Paint();
public RachetBasic(Context context) {
super(context);
}
public RachetBasic(Context context, AttributeSet attrs) {
super(context, attrs);
}
public RachetBasic(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onSizeChanged(int width, int height, int oldw, int oldh) {
super.onSizeChanged(width, height, oldw, oldh);
squarePaint.setAntiAlias(true);
squarePaint.setDither(true);
squarePaint.setStyle(Paint.Style.STROKE);
squarePaint.setStrokeCap(Paint.Cap.SQUARE);
squarePaint.setStrokeWidth(80);
squarePaint.setColor(Color.BLUE);
bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
canvas = new Canvas(bitmap);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(bitmap, 0, 0, bitmapPaint);
canvas.drawPath(squarePath, squarePaint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
if (event.getAction() == MotionEvent.ACTION_DOWN) {
squarePath.moveTo(x, y);
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
squarePath.lineTo(x, y);
} else if (event.getAction() == MotionEvent.ACTION_UP) {
squarePath.lineTo(x, y);
canvas.drawPath(squarePath, squarePaint);
squarePath.reset();
}
invalidate();
return true;
}
}
public class MainActivity extends androidx.appcompat.app.AppCompatActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new RachetBasic(MainActivity.this));
}
}
英文:
I build this class to draw on screen to implement some brushes created via differents Paints and paths.
Currently is drawing a square based on user touch movement, but the draw path is being rotated by the draw direction of the touch. I tried to apply a rect without no luck and I don't found any related info about this phenom
EDIT :
This image is from current result
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.util.AttributeSet;
import android.view.MotionEvent;
public class RachetBasic extends androidx.appcompat.widget.AppCompatImageView {
private Canvas canvas;
private Bitmap bitmap;
private Paint bitmapPaint = new Paint(Paint.DITHER_FLAG);
private Path squarePath = new Path();
private Paint squarePaint = new Paint();
public RachetBasic(Context context) {
super(context);
}
public RachetBasic(Context context, AttributeSet attrs) {
super(context, attrs);
}
public RachetBasic(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
}
@Override
protected void onSizeChanged(int width, int height, int oldw, int oldh) {
super.onSizeChanged(width, height, oldw, oldh);
squarePaint.setAntiAlias(true);
squarePaint.setDither(true);
squarePaint.setStyle(Paint.Style.STROKE);
squarePaint.setStrokeCap(Paint.Cap.SQUARE);
squarePaint.setStrokeWidth(80);
squarePaint.setColor(Color.BLUE);
bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
canvas = new Canvas(bitmap);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(bitmap, 0, 0, bitmapPaint);
canvas.drawPath(squarePath, squarePaint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float x = event.getX();
float y = event.getY();
if (event.getAction() == MotionEvent.ACTION_DOWN) {
squarePath.moveTo(x, y);
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
squarePath.lineTo(x, y);
} else if (event.getAction() == MotionEvent.ACTION_UP) {
squarePath.lineTo(x, y);
canvas.drawPath(squarePath, squarePaint);
squarePath.reset();
}
invalidate();
return true;
}
}
public class MainActivity extends androidx.appcompat.app.AppCompatActivity {
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(new RachetBasic(MainActivity.this));
}
}
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