CODEWITHSUNDEEP
android
Someone Somewhere
Someone Somewhere

Reputation: 23787

What's this weird drawArc() / arcTo() bug (graphics glitch) in Android?

I ran my code on my Nexus 7 whilst it still had Android 4.3 installed. I then upgraded to Android 4.4 and ran my code again. Below are my findings on a weird Canvas.drawArc() / Path.arcTo() bug (graphics glitch) ...

First Method

@Override
protected void onDraw(Canvas canvas)
{
    super.onDraw(canvas);

    //draw Background
    canvas.drawRect(mOuterArcRectangle, mBackgroundPaint);

    //draw arc
    Path path = new Path();
    path.arcTo(mInnerArcRectangle, mAngleStart, mSweep);
    canvas.drawPath(path, mPaint);
}

State

mOuterArcRectangle = RectF(0.0, 0.0, 1080.0, 1080.0)
mInnerArcRectangle = RectF(150.0, 150.0, 930.0, 930.0)
mAngleStart = 120
mSweep = 135

causes this result... enter image description here

2nd method

@Override
protected void onDraw(Canvas canvas)
{
    super.onDraw(canvas);

    //draw Background
    canvas.drawRect(mOuterArcRectangle, mBackgroundPaint);

    //draw arc
    canvas.drawArc(mInnerArcRectangle, mAngleStart, mSweep, false, mPaint);
}

State

mOuterArcRectangle = RectF(0.0, 0.0, 1080.0, 1080.0)
mInnerArcRectangle = RectF(150.0, 150.0, 930.0, 930.0)
mAngleStart = 120
mSweep = 135

causes this result... enter image description here

On Android 4.4 Either method results in (what I would consider successful)

enter image description here

Solution ? Is there a workaround for this problem? Is it a known problem ?

Upvotes: 2

Views: 996

Answers (1)

Someone Somewhere
Someone Somewhere

Reputation: 23787

I've fixed it simply by adding 0.5f to the sweep angle before drawing the arc.

Upvotes: 2

Related Questions