android - Blurry offset paths when canvas is scaled under hardware acceleration -

my application uses canvas scale can specify path points in meters instead of pixels. when scale canvas, draw line using path.lineto(), hardware acceleration on, line blurry , offset. not happen hardware acceleration off or canvas.drawline().

here code reproduce problem:

package com.example.canvasproblem;  import android.app.activity; import android.content.context; import android.graphics.canvas; import android.graphics.paint; import android.graphics.path; import android.os.bundle; import android.view.view;  public class mainactivity extends activity {     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);          setcontentview(new myview(this));     }      class myview extends view {         paint pen = new paint();         public myview(context context) {             super(context);             pen.setstyle(paint.style.stroke);             pen.setstrokewidth(1f); // 1 meters wide             //this.setlayertype(layer_type_software, null);         }         protected void ondraw(canvas canvas) {             float width_meter = 10.0f; // width of canvas in meters             float width_pxl = canvas.getwidth(); // width of canvas in pixels             float height_pxl = canvas.getheight(); // height of canvas in pixels              canvas.save();             canvas.translate(width_pxl/2, height_pxl/2); // make center of canvas (0,0)             canvas.scale(width_pxl/width_meter, width_pxl/width_meter); // convert meters              // path             path path = new path();             path.moveto(0, 0);             path.lineto(0, 4);             canvas.drawpath(path, pen);              // line             canvas.drawline(0, 0, 0, 4, pen);              canvas.restore();         }     } } 

here screenshot of problem output (the correct drawline() shown on top of lineto()):

screenshot.png

the hardware 1024x768 tablet, running android 4.1.1. processor rockchip rk30.

my preference use path's hardware acceleration, rounded joins between points , speed. please let me know if doing wrong create problem. thank you

be gentle, first post.

this limitation of hardware accelerated renderer. paths rasterized @ native size before transform. in case, path transformed 1x4 texture. texture scaled @ draw time. work around this, scale path directly using path.transform(matrix). can use scaled coordinates when building path.