CODEWITHSUNDEEP
androidmathpie-chart
Boots
Boots

Reputation: 224

Center of Pie Segment - Android

I'm using the HoloGraphLibrary for Android, but I need the percentage of each segment inside the pie chart (in its segment).

Because there isn't any coordinate system, I can't just find the segment and add some text, so I need a clever trick to do it. The only values I have at my disposal are: - The midX and midY coordinate of the pie chart - The inner and outer radius - each segments sweep (or angle our of 360 it covers)

I've managed to get the Y coordinate of the label, but using the same method for the X coordinate isn't yielding the correct result. This is the code I have so far:

canvas.drawText(slice.getTitle(), (float) (midX + (innerRadius + (radius - innerRadius)/2)*-1*Math.cos((currentSweep-padding)/2*(Math.PI/180) )), (float) (midY - (innerRadius + (radius - innerRadius)/2)*Math.cos((currentSweep)/2*(Math.PI/180))), paint);

Can anyone help with centring the label in the segment?

Thanks

Upvotes: 1

Views: 420

Answers (2)

Ankita Shah
Ankita Shah

Reputation: 1904

Try this. It's working for me.

canvas.drawText(slice.getTitle(),
                        (float) (midX + (innerRadius + (radius - innerRadius)/2)*Math.sin((currentSweep)*(Math.PI/360) )),
                        (float) (midY - (innerRadius + (radius - innerRadius)/2)*Math.cos((currentSweep)*(Math.PI/360))),
                        mPaint);

Upvotes: 0

user3743997
user3743997

Reputation: 21

Ok my bad, This is an answer :

// add a text title centered in each slice :
        textAngle += currentSweep;
        mBlackColorPaint.setTextAlign(Paint.Align.CENTER);
        System.out.println("title : " + slice.getTitle() +  "Sweep : "+currentSweep + " Angle = "+currentAngle);
        canvas.drawText(slice.getTitle(),
                (float) (midX + (innerRadius + (radius - innerRadius)/2)*Math.sin((textAngle)*(Math.PI/360) )),
                (float) (midY - (innerRadius + (radius - innerRadius)/2)*Math.cos((textAngle)*(Math.PI/360))),
                mBlackColorPaint);
        textAngle += currentSweep;

put this in the onDraw() method after setting the Region object

Upvotes: 2

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