draw.cpp Example File

    /* Copyright (c) 2012, 2013  Stuart MacMartin.
    *
    * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
    * INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
    * PARTICULAR PURPOSE AND NONINFRINGEMENT.
    * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
    * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
    */

    #include <QImage>
    #include <QPainter>

    #include "draw.h"

    /*
     * Draw a circle in an image of the specified size.
     */
    QImage Draw::drawCircle(const QSize &size)
    {
        // Create an image of the appropriate size.
        // The underlying data is reference counted so is cleaned up as needed.
        QImage image(size, QImage::Format_RGB32);
        image.fill(Qt::black);

        // Pick an arbitrary size for the circle
        const int centerX = size.width() / 2;
        const int centerY = size.height() / 2;
        const int radius = std::min(centerX, centerY) * 2 / 3;
        const int diameter = radius * 2;

        // Draw the circle!
        QPainter painter(&image);
        painter.setPen(Qt::white);
        painter.drawEllipse(centerX-radius, centerY-radius, diameter, diameter);

        return image;
    }
    /*
     * Draw a rectangle in an image of the specified size.
     */
    QImage Draw::drawSquare(const QSize &size)
    {
        QImage image(size, QImage::Format_RGB32);
        image.fill(Qt::black);

        // Pick an arbitrary size for the square
        const int centerX = size.width() / 2;
        const int centerY = size.height() / 2;
        const int w = size.width()  * 2 / 3;
        const int h = size.height() * 2 / 3;

        // Draw the square!
        QPainter painter(&image);
        painter.setPen(Qt::white);
        painter.drawRect(centerX - w/2, centerY - h/2, w, h);

        return image;
    }
    /*
     * Replicate an image into another image.
     * Scale down the replicant if necessary to fit.
     */
    QImage Draw::replicate(const QSize &destinationSize, const QImage &replicant, int numRows, int numCols)
    {
        if (numRows <= 0 || numCols <= 0)
            return QImage(); // illegal call

        QImage destination(destinationSize, QImage::Format_RGB32);

        const int numPixelsX = destinationSize.width()  / numCols;
        const int numPixelsY = destinationSize.height() / numRows;

        const int extraPixelsX = destination.width()  - (numPixelsX * numCols);
        const int extraPixelsY = destination.height() - (numPixelsY * numRows);

        const int offsetX = extraPixelsX / 2;
        const int offsetY = extraPixelsY / 2;

        // Fill the extra pixels and overwrite the last contents
        // in case there is any transparency
        destination.fill(Qt::black);

        // Replicate
        QPainter painter(&destination);
        for (int rows = 0; rows < numRows; ++rows) {
            const int y = offsetY + rows * numPixelsY;
            for (int cols = 0; cols < numCols; ++cols) {
                painter.drawImage(offsetX + cols * numPixelsX, y, replicant);
            }
        }

        return destination;
    }