center_vertical image span

CenterVerticalImageSpan.java

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.text.style.ImageSpan;

import androidx.annotation.Px;

public class CenterVerticalImageSpan extends ImageSpan {
    private static final int STANDARD_PAD_WIDTH = 0;
    @Px
    private final int mPad;


    public CenterVerticalImageSpan(Context context, int resourceId) {
        super(context, resourceId);
        mPad = STANDARD_PAD_WIDTH;
    }

    public CenterVerticalImageSpan(Drawable drawable) {
        super(drawable);
        mPad = STANDARD_PAD_WIDTH;
    }

    public CenterVerticalImageSpan(Drawable drawable, @Px int padding) {
        super(drawable);
        mPad = padding;
    }

    @Override
    public int getSize(Paint paint, CharSequence text, int start, int end,
                       Paint.FontMetricsInt fontMetricsInt) {
        Drawable drawable = getDrawable();
        Rect rect = drawable.getBounds();
        if (fontMetricsInt != null) {
            Paint.FontMetricsInt fmPaint = paint.getFontMetricsInt();
            int fontHeight = fmPaint.bottom - fmPaint.top;
            int drHeight = rect.bottom - rect.top;

            int top = drHeight / 2 - fontHeight / 4;
            int bottom = drHeight / 2 + fontHeight / 4;

            fontMetricsInt.ascent = -bottom;
            fontMetricsInt.top = -bottom;
            fontMetricsInt.bottom = top;
            fontMetricsInt.descent = top;
        }
        return rect.right + mPad;
    }

    @Override
    public void draw(Canvas canvas, CharSequence text, int start, int end,
                     float x, int top, int y, int bottom, Paint paint) {
        Drawable drawable = getDrawable();
        canvas.save();
        int transY;
        Paint.FontMetricsInt fm = paint.getFontMetricsInt();
        transY = y + (fm.descent + fm.ascent) / 2
                - drawable.getBounds().bottom / 2;
        canvas.translate(x + mPad, transY);
        drawable.draw(canvas);
        canvas.restore();
    }
}