ScatterGraphView.java

/* 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 uk.ac.cam.cl.dtg.snowdon;

import android.content.Context;
import android.graphics.Canvas;
import android.util.AttributeSet;

/**
 * Inherits from GraphView and draws a graph with a simple marker at data
 * points.
 */
public class ScatterGraphView extends GraphView {
    /**
     * Creates a new ScatterGraphView and sets layout parameters from XML via
     * GraphView.
     *
     * @param context
     * @param attributes
     */
    public ScatterGraphView(Context context, AttributeSet attributes) {
        super(context, attributes);
    }

    @Override
    protected void drawPlot(Canvas canvas) {
        for (int set = 0; set < mData.length; set++) {
            try {
                int setColour = mDataSetColours[set];
                mAscendingPaint.setColor(setColour);
                mDescendingPaint.setColor(setColour);
            } catch (IndexOutOfBoundsException e) {
                // Just carry on using the last colour
            }

            for (int i = 0; i < mData[set][0].length - 1; i++) {
                float[] coords = calcCoordinates(set, i);
                if (Float.isNaN(mData[set][1][i + 1])) {
                    // Don't draw anything for NaNs, as it doesn't make sense to
                } else if (Float.isNaN(mData[set][1][i])
                        && Float.isNaN(mData[set][1][i + 1]) == false) {
                    // More NaNs
                } else if (Float.isNaN(coords[1]) || Float.isNaN(coords[3])) {
                    // Yet more NaNs
                } else if (coords[3] < coords[1]) {
                    // If the data is increasing, draw in the ascending style...
                    drawAscendingSection(canvas, coords);
                } else {
                    // ...otherwise, draw in the descending style
                    drawDescendingSection(canvas, coords);
                }
            }

            float[] coords = calcCoordinates(set, mData[set][0].length - 2);
            canvas.drawLine(coords[2] - mAscendingPaint.getStrokeWidth() * 3, coords[3], coords[2] + mAscendingPaint.getStrokeWidth() * 3, coords[3], mAscendingPaint);
            canvas.drawLine(coords[2], coords[3] - mAscendingPaint.getStrokeWidth() * 3, coords[2], coords[3] + mAscendingPaint.getStrokeWidth() * 3, mAscendingPaint);
        }
    }

    @Override
    protected void drawAscendingSection(Canvas canvas, float[] coords) {
        canvas.drawLine(coords[0] - mAscendingPaint.getStrokeWidth() * 3, coords[1], coords[0] + mAscendingPaint.getStrokeWidth() * 3, coords[1], mAscendingPaint);
        canvas.drawLine(coords[0], coords[1] - mAscendingPaint.getStrokeWidth() * 3, coords[0], coords[1] + mAscendingPaint.getStrokeWidth() * 3, mAscendingPaint);
    }

    @Override
    protected void drawDescendingSection(Canvas canvas, float[] coords) {
        canvas.drawLine(coords[0] - mDescendingPaint.getStrokeWidth() * 3, coords[1], coords[0] + mDescendingPaint.getStrokeWidth() * 3, coords[1], mDescendingPaint);
        canvas.drawLine(coords[0], coords[1] - mDescendingPaint.getStrokeWidth() * 3, coords[0], coords[1] + mDescendingPaint.getStrokeWidth() * 3, mDescendingPaint);
    }
}