OutlineTextView.java

/*
 * Copyright (C) 2013 YIXIA.COM
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package io.vov.vitamio.widget;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.text.Layout;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.widget.TextView;

/**
 * Display text with border, use the same XML attrs as
 * {@link android.widget.TextView}, except that {@link OutlineTextView} will
 * transform the shadow to border
 */
public class OutlineTextView extends TextView {
  private TextPaint mTextPaint;
  private TextPaint mTextPaintOutline;
  private String mText = "";
  private int mAscent = 0;
  private float mBorderSize;
  private int mBorderColor;
  private int mColor;
  private float mSpacingMult = 1.0f;
  private float mSpacingAdd = 0;
  private boolean mIncludePad = true;

  public OutlineTextView(Context context) {
    super(context);
    initPaint();
  }

  public OutlineTextView(Context context, AttributeSet attrs) {
    super(context, attrs);
    initPaint();
  }

  public OutlineTextView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    initPaint();
  }

  private void initPaint() {
    mTextPaint = new TextPaint();
    mTextPaint.setAntiAlias(true);
    mTextPaint.setTextSize(getTextSize());
    mTextPaint.setColor(mColor);
    mTextPaint.setStyle(Paint.Style.FILL);
    mTextPaint.setTypeface(getTypeface());

    mTextPaintOutline = new TextPaint();
    mTextPaintOutline.setAntiAlias(true);
    mTextPaintOutline.setTextSize(getTextSize());
    mTextPaintOutline.setColor(mBorderColor);
    mTextPaintOutline.setStyle(Paint.Style.STROKE);
    mTextPaintOutline.setTypeface(getTypeface());
    mTextPaintOutline.setStrokeWidth(mBorderSize);
  }

  public void setText(String text) {
    super.setText(text);
    mText = text.toString();
    requestLayout();
    invalidate();
  }

  public void setTextSize(float size) {
    super.setTextSize(size);
    requestLayout();
    invalidate();
    initPaint();
  }

  public void setTextColor(int color) {
    super.setTextColor(color);
    mColor = color;
    invalidate();
    initPaint();
  }

  public void setShadowLayer(float radius, float dx, float dy, int color) {
    super.setShadowLayer(radius, dx, dy, color);
    mBorderSize = radius;
    mBorderColor = color;
    requestLayout();
    invalidate();
    initPaint();
  }

  public void setTypeface(Typeface tf, int style) {
    super.setTypeface(tf, style);
    requestLayout();
    invalidate();
    initPaint();
  }

  public void setTypeface(Typeface tf) {
    super.setTypeface(tf);
    requestLayout();
    invalidate();
    initPaint();
  }

  @Override
  protected void onDraw(Canvas canvas) {
    Layout layout = new StaticLayout(getText(), mTextPaintOutline, getWidth(), Layout.Alignment.ALIGN_CENTER, mSpacingMult, mSpacingAdd, mIncludePad);
    layout.draw(canvas);
    layout = new StaticLayout(getText(), mTextPaint, getWidth(), Layout.Alignment.ALIGN_CENTER, mSpacingMult, mSpacingAdd, mIncludePad);
    layout.draw(canvas);
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    Layout layout = new StaticLayout(getText(), mTextPaintOutline, measureWidth(widthMeasureSpec), Layout.Alignment.ALIGN_CENTER, mSpacingMult, mSpacingAdd, mIncludePad);
    int ex = (int) (mBorderSize * 2 + 1);
    setMeasuredDimension(measureWidth(widthMeasureSpec) + ex, measureHeight(heightMeasureSpec) * layout.getLineCount() + ex);
  }

  private int measureWidth(int measureSpec) {
    int result = 0;
    int specMode = MeasureSpec.getMode(measureSpec);
    int specSize = MeasureSpec.getSize(measureSpec);

    if (specMode == MeasureSpec.EXACTLY) {
      result = specSize;
    } else {
      result = (int) mTextPaintOutline.measureText(mText) + getPaddingLeft() + getPaddingRight();
      if (specMode == MeasureSpec.AT_MOST) {
        result = Math.min(result, specSize);
      }
    }

    return result;
  }

  private int measureHeight(int measureSpec) {
    int result = 0;
    int specMode = MeasureSpec.getMode(measureSpec);
    int specSize = MeasureSpec.getSize(measureSpec);

    mAscent = (int) mTextPaintOutline.ascent();
    if (specMode == MeasureSpec.EXACTLY) {
      result = specSize;
    } else {
      result = (int) (-mAscent + mTextPaintOutline.descent()) + getPaddingTop() + getPaddingBottom();
      if (specMode == MeasureSpec.AT_MOST) {
        result = Math.min(result, specSize);
      }
    }
    return result;
  }
}