src/com/android/camera/ui/ProgressRenderer.java

/*
 * Copyright (C) 2013 The Android Open Source Project
 *
 * 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 com.android.camera.ui;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.RectF;

import com.android.camera2.R;

/**
 * Renders a circular progress bar on the screen.
 */
public class ProgressRenderer {

    public static interface VisibilityListener {
        public void onHidden();
    }

    private final int mProgressRadius;
    private final Paint mProgressBasePaint;
    private final Paint mProgressPaint;

    private RectF mArcBounds = new RectF(0, 0, 1, 1);
    private int mProgressAngleDegrees = 270;
    private boolean mVisible = false;
    private VisibilityListener mVisibilityListener;

    /**
     * After we reach 100%, keep on painting the progress for another x milliseconds
     * before hiding it.
     */
    private static final int SHOW_PROGRESS_X_ADDITIONAL_MS = 100;

    /** When to hide the progress indicator. */
    private long mTimeToHide = 0;

    public ProgressRenderer(Context context) {
        mProgressRadius = context.getResources().getDimensionPixelSize(R.dimen.pie_progress_radius);
        int pieProgressWidth = context.getResources().getDimensionPixelSize(
                R.dimen.pie_progress_width);
        mProgressBasePaint = createProgressPaint(pieProgressWidth, 0.2f);
        mProgressPaint = createProgressPaint(pieProgressWidth, 1.0f);
    }

    /**
     * Sets or replaces a visiblity listener.
     */
    public void setVisibilityListener(VisibilityListener listener) {
        mVisibilityListener = listener;
    }

    /**
     * Shows a progress indicator. If the progress is '100', the progress
     * indicator will be hidden.
     *
     * @param percent the progress in percent (0-100).
     */
    public void setProgress(int percent) {
        // Clamp the value.
        percent = Math.min(100, Math.max(percent, 0));
        mProgressAngleDegrees = (int) ((360f / 100) * percent);

        // We hide the progress once we drew the 100% state once.
        if (percent < 100) {
            mVisible = true;
            mTimeToHide = System.currentTimeMillis() + SHOW_PROGRESS_X_ADDITIONAL_MS;
        }
    }

    /**
     * Draw the current progress (if < 100%) centered at the given location.
     */
    public void onDraw(Canvas canvas, int centerX, int centerY) {
        if (!mVisible) {
            return;
        }
        mArcBounds = new RectF(centerX - mProgressRadius, centerY - mProgressRadius, centerX
                + mProgressRadius,
                centerY + mProgressRadius);

        canvas.drawCircle(centerX, centerY, mProgressRadius, mProgressBasePaint);
        canvas.drawArc(mArcBounds, -90, mProgressAngleDegrees, false, mProgressPaint);

        // After we reached 100%, we paint the progress renderer for another x
        // milliseconds until we hide it.
        if (mProgressAngleDegrees == 360 && System.currentTimeMillis() > mTimeToHide) {
            mVisible = false;
            if (mVisibilityListener != null) {
                mVisibilityListener.onHidden();
            }
        }
    }

    /**
     * @return Whether the progress renderer is visible.
     */
    public boolean isVisible() {
        return mVisible;
    }

    private static Paint createProgressPaint(int width, float alpha) {
        Paint paint = new Paint();
        paint.setAntiAlias(true);
        // 20% alpha.
        paint.setColor(Color.argb((int) (alpha * 255), 255, 255, 255));
        paint.setStrokeWidth(width);
        paint.setStyle(Paint.Style.STROKE);
        return paint;
    }
}