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longkai/LogoView.java

Created March 28, 2015 09:50
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Revisions

  1. longkai created this gist Mar 28, 2015.
    164 changes: 164 additions & 0 deletions LogoView.java
    View file
    Original file line number Diff line number Diff line change
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    /*
    * The MIT License (MIT)
    *
    * Copyright (c) 2015 longkai
    *
    * The software shall be used for good, not evil.
    */

    package android.support.widget;

    import android.annotation.TargetApi;
    import android.content.Context;
    import android.content.res.TypedArray;
    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.graphics.Path;
    import android.graphics.drawable.Drawable;
    import android.os.Build;
    import android.support.R;
    import android.util.AttributeSet;
    import android.util.TypedValue;
    import android.view.View;

    /**
    * A logo view with an isosceles triangle.
    *
    * To use it, provide you distinct angle and the largest edge.
    *
    * @author longkai
    */
    public class LogoView extends View {
    private Drawable logo;
    private int angle;
    private int color;
    private int edge;

    private Paint mPaint;
    private Path mPath;

    public LogoView(Context context) {
    this(context, null);
    }

    public LogoView(Context context, AttributeSet attrs) {
    super(context, attrs);
    bootstrap(context, attrs, 0, 0);
    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public LogoView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    bootstrap(context, attrs, defStyleAttr, 0);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public LogoView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    super(context, attrs, defStyleAttr, defStyleRes);
    bootstrap(context, attrs, defStyleAttr, defStyleRes);
    }

    private void bootstrap(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
    TypedArray array = context.obtainStyledAttributes(attrs, R.styleable.LogoView, defStyleAttr, defStyleRes);
    logo = array.getDrawable(R.styleable.LogoView__logo);
    angle = array.getInt(R.styleable.LogoView_triangle_angle, 120);
    color = array.getColor(R.styleable.LogoView_triangle_color, Color.WHITE);
    // default to 10dip, may not satisfy you, provide your own
    edge = array.getDimensionPixelSize(R.styleable.LogoView_triangle_edge,
    (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 10, getResources().getDisplayMetrics()));
    array.recycle();

    mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    mPath = new Path();
    }

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

    // first, draw the logo if there' s one and center it
    if (logo != null) {
    int width = logo.getIntrinsicWidth();
    int height = logo.getIntrinsicHeight();
    logo.setBounds(
    (getWidth() - width) / 2,
    (getHeight() - height) / 2,
    (getWidth() + width) / 2,
    (getHeight() + height) / 2
    );

    logo.draw(canvas);
    }

    double tan = Math.tan(Math.toRadians(angle * 1f / 2));
    if (tan > 0f) {
    int h = (int) (edge / 2f / tan);
    int x = getWidth() / 2;
    int y = getHeight() - getPaddingBottom();

    // * (a)
    // ***
    // *****
    // *******
    // (b) (c)
    // (x,y)

    // don' t forget to reset path
    mPath.reset();
    mPath.setFillType(Path.FillType.EVEN_ODD);

    // apply three points
    mPath.moveTo(x, y - h); // a
    mPath.lineTo(x - edge / 2, y); // b
    mPath.lineTo(x + edge / 2, y); // c

    // done
    mPath.close();

    mPaint.setColor(color);

    // draw the triangle
    canvas.drawPath(mPath, mPaint);
    }

    canvas.restore();
    }

    public int getAngle() {
    return angle;
    }

    public void setAngle(int angle) {
    this.angle = angle;
    invalidate();
    }

    public int getColor() {
    return color;
    }

    public void setColor(int color) {
    this.color = color;
    invalidate();
    }

    public int getEdge() {
    return edge;
    }

    public void setEdge(int edge) {
    this.edge = edge;
    invalidate();
    }

    public Drawable getLogo() {
    return logo;
    }

    public void setLogo(Drawable logo) {
    this.logo = logo;
    invalidate();
    }
    }