Example usage for android.graphics Canvas drawLines

Introduction

In this page you can find the example usage for android.graphics Canvas drawLines.

Prototype

public void drawLines(@Size(multiple = 4) @NonNull float[] pts, int offset, int count, @NonNull Paint paint) 

Source Link

Document

Draw a series of lines.

Usage

From source file:cn.androidy.androiddevelopmentpatterns.interactivechart.InteractiveLineGraphView.java

/**
 * Draws the chart axes and labels onto the canvas.
 *///  w ww  .  j  a v a2s .com
private void drawAxes(Canvas canvas) {
    // Computes axis stops (in terms of numerical value and position on screen)
    int i;

    computeAxisStops(mCurrentViewport.left, mCurrentViewport.right, mContentRect.width() / mMaxLabelWidth / 2,
            mXStopsBuffer);
    computeAxisStops(mCurrentViewport.top, mCurrentViewport.bottom, mContentRect.height() / mLabelHeight / 2,
            mYStopsBuffer);

    // Avoid unnecessary allocations during drawing. Re-use allocated
    // arrays and only reallocate if the number of stops grows.
    if (mAxisXPositionsBuffer.length < mXStopsBuffer.numStops) {
        mAxisXPositionsBuffer = new float[mXStopsBuffer.numStops];
    }
    if (mAxisYPositionsBuffer.length < mYStopsBuffer.numStops) {
        mAxisYPositionsBuffer = new float[mYStopsBuffer.numStops];
    }
    if (mAxisXLinesBuffer.length < mXStopsBuffer.numStops * 4) {
        mAxisXLinesBuffer = new float[mXStopsBuffer.numStops * 4];
    }
    if (mAxisYLinesBuffer.length < mYStopsBuffer.numStops * 4) {
        mAxisYLinesBuffer = new float[mYStopsBuffer.numStops * 4];
    }

    // Compute positions
    for (i = 0; i < mXStopsBuffer.numStops; i++) {
        mAxisXPositionsBuffer[i] = getDrawX(mXStopsBuffer.stops[i]);
    }
    for (i = 0; i < mYStopsBuffer.numStops; i++) {
        mAxisYPositionsBuffer[i] = getDrawY(mYStopsBuffer.stops[i]);
    }

    // Draws grid lines using drawLines (faster than individual drawLine calls)
    for (i = 0; i < mXStopsBuffer.numStops; i++) {
        mAxisXLinesBuffer[i * 4 + 0] = (float) Math.floor(mAxisXPositionsBuffer[i]);
        mAxisXLinesBuffer[i * 4 + 1] = mContentRect.top;
        mAxisXLinesBuffer[i * 4 + 2] = (float) Math.floor(mAxisXPositionsBuffer[i]);
        mAxisXLinesBuffer[i * 4 + 3] = mContentRect.bottom;
    }
    canvas.drawLines(mAxisXLinesBuffer, 0, mXStopsBuffer.numStops * 4, mGridPaint);

    for (i = 0; i < mYStopsBuffer.numStops; i++) {
        mAxisYLinesBuffer[i * 4 + 0] = mContentRect.left;
        mAxisYLinesBuffer[i * 4 + 1] = (float) Math.floor(mAxisYPositionsBuffer[i]);
        mAxisYLinesBuffer[i * 4 + 2] = mContentRect.right;
        mAxisYLinesBuffer[i * 4 + 3] = (float) Math.floor(mAxisYPositionsBuffer[i]);
    }
    canvas.drawLines(mAxisYLinesBuffer, 0, mYStopsBuffer.numStops * 4, mGridPaint);

    // Draws X labels
    int labelOffset;
    int labelLength;
    mLabelTextPaint.setTextAlign(Paint.Align.CENTER);
    for (i = 0; i < mXStopsBuffer.numStops; i++) {
        // Do not use String.format in high-performance code such as onDraw code.
        labelLength = formatFloat(mLabelBuffer, mXStopsBuffer.stops[i], mXStopsBuffer.decimals);
        labelOffset = mLabelBuffer.length - labelLength;
        canvas.drawText(mLabelBuffer, labelOffset, labelLength, mAxisXPositionsBuffer[i],
                mContentRect.bottom + mLabelHeight + mLabelSeparation, mLabelTextPaint);
    }

    // Draws Y labels
    mLabelTextPaint.setTextAlign(Paint.Align.RIGHT);
    for (i = 0; i < mYStopsBuffer.numStops; i++) {
        // Do not use String.format in high-performance code such as onDraw code.
        labelLength = formatFloat(mLabelBuffer, mYStopsBuffer.stops[i], mYStopsBuffer.decimals);
        labelOffset = mLabelBuffer.length - labelLength;
        canvas.drawText(mLabelBuffer, labelOffset, labelLength, mContentRect.left - mLabelSeparation,
                mAxisYPositionsBuffer[i] + mLabelHeight / 2, mLabelTextPaint);
    }
}

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From source file:de.tum.in.tumcampus.auxiliary.calendar.DayView.java

private void drawGridBackground(Rect r, Canvas canvas, Paint p) {
    Style savedStyle = p.getStyle();

    final float stopX = computeDayLeftPosition(mNumDays);
    float y = 0;/*from   ww  w .  j  a v  a2s.c  o m*/
    final float deltaY = mCellHeight + HOUR_GAP;
    int linesIndex = 0;
    final float startY = 0;
    final float stopY = HOUR_GAP + 24 * (mCellHeight + HOUR_GAP);
    float x = mHoursWidth;

    // Draw the inner horizontal grid lines
    p.setColor(mCalendarGridLineInnerHorizontalColor);
    p.setStrokeWidth(GRID_LINE_INNER_WIDTH);
    p.setAntiAlias(false);
    y = 0;
    linesIndex = 0;
    for (int hour = 0; hour <= 24; hour++) {
        mLines[linesIndex++] = GRID_LINE_LEFT_MARGIN;
        mLines[linesIndex++] = y;
        mLines[linesIndex++] = stopX;
        mLines[linesIndex++] = y;
        y += deltaY;
    }
    if (mCalendarGridLineInnerVerticalColor != mCalendarGridLineInnerHorizontalColor) {
        canvas.drawLines(mLines, 0, linesIndex, p);
        linesIndex = 0;
        p.setColor(mCalendarGridLineInnerVerticalColor);
    }

    // Draw the inner vertical grid lines
    for (int day = 0; day <= mNumDays; day++) {
        x = computeDayLeftPosition(day);
        mLines[linesIndex++] = x;
        mLines[linesIndex++] = startY;
        mLines[linesIndex++] = x;
        mLines[linesIndex++] = stopY;
    }
    canvas.drawLines(mLines, 0, linesIndex, p);

    // Restore the saved style.
    p.setStyle(savedStyle);
    p.setAntiAlias(true);
}

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