fix: issue [#185](#185) drawTextOnBitmap 部分特殊文字会出现IndexOutOfBoundsException【必现.

Author: errnull

library/src/main/java/com/opensource/svgaplayer/drawer/SVGACanvasDrawer.kt

@@ -3,9 +3,8 @@ package com.opensource.svgaplayer.drawer
 import android.annotation.TargetApi
 import android.graphics.*
 import android.os.Build
-import android.text.BoringLayout
-import android.text.StaticLayout
-import android.text.TextUtils
+import android.text.*
+import android.text.style.StyleSpan
 import android.widget.FrameLayout
 import android.widget.ImageView
 import com.opensource.svgaplayer.SVGADynamicEntity
@@ -245,15 +244,16 @@ internal class SVGACanvasDrawer(videoItem: SVGAVideoEntity, val dynamicItem: SVG
                     textBitmap = it
                 } ?: kotlin.run {
                     textBitmap = Bitmap.createBitmap(drawingBitmap.width, drawingBitmap.height, Bitmap.Config.ARGB_8888)
+                    val drawRect = Rect(0, 0, drawingBitmap.width, drawingBitmap.height)
                     val textCanvas = Canvas(textBitmap)
                     drawingTextPaint.isAntiAlias = true
-                    val bounds = Rect()
-                    drawingTextPaint.getTextBounds(drawingText, 0, drawingText.length, bounds)
-                    val x = (drawingBitmap.width - bounds.width()) / 2.0
-                    val targetRectTop = 0
-                    val targetRectBottom = drawingBitmap.height
-                    val y = (targetRectBottom + targetRectTop - drawingTextPaint.fontMetrics.bottom - drawingTextPaint.fontMetrics.top) / 2
-                    textCanvas.drawText(drawingText, x.toFloat(), y, drawingTextPaint)
+                    drawingTextPaint.setStyle(Paint.Style.FILL);
+                    drawingTextPaint.setTextAlign(Paint.Align.CENTER);
+                    val fontMetrics = drawingTextPaint.getFontMetrics();
+                    val top = fontMetrics.top
+                    val bottom = fontMetrics.bottom
+                    val baseLineY = drawRect.centerY() - top/2 - bottom/2
+                    textCanvas.drawText(drawingText, drawRect.centerX().toFloat(),baseLineY,drawingTextPaint);
                     drawTextCache.put(imageKey, textBitmap as Bitmap)
                 }
             }