working versiom

IntelliPhoto/Scribble/scribblearea.cpp

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+// ---------- scribblearea.cpp ----------
+
+#include <QtWidgets>
+#include "scribblearea.h"
+
+ScribbleArea::ScribbleArea(QWidget *parent)
+    : QWidget(parent)
+{
+    // Roots the widget to the top left even if resized
+    setAttribute(Qt::WA_StaticContents);
+
+    // Set defaults for the monitored variables
+    modified = false;
+    scribbling = false;
+    myPenWidth = 1;
+    myPenColor = Qt::blue;
+}
+
+// Used to load the image and place it in the widget
+bool ScribbleArea::openImage(const QString &fileName)
+{
+    // Holds the image
+    QImage loadedImage;
+
+    // If the image wasn't loaded leave this function
+    if (!loadedImage.load(fileName))
+        return false;
+
+    QSize newSize = loadedImage.size().expandedTo(size());
+    resizeImage(&loadedImage, newSize);
+    image = loadedImage;
+    modified = false;
+    update();
+    return true;
+}
+
+// Save the current image
+bool ScribbleArea::saveImage(const QString &fileName, const char *fileFormat)
+{
+    // Created to hold the image
+    QImage visibleImage = image;
+    resizeImage(&visibleImage, size());
+
+    if (visibleImage.save(fileName, fileFormat)) {
+        modified = false;
+        return true;
+    } else {
+        return false;
+    }
+}
+
+// Used to change the pen color
+void ScribbleArea::setPenColor(const QColor &newColor)
+{
+    myPenColor = newColor;
+}
+
+// Used to change the pen width
+void ScribbleArea::setPenWidth(int newWidth)
+{
+    myPenWidth = newWidth;
+}
+
+// Color the image area with white
+void ScribbleArea::clearImage()
+{
+    image.fill(qRgb(255, 255, 255));
+    modified = true;
+    update();
+}
+
+// If a mouse button is pressed check if it was the
+// left button and if so store the current position
+// Set that we are currently drawing
+void ScribbleArea::mousePressEvent(QMouseEvent *event)
+{
+    if (event->button() == Qt::LeftButton) {
+        lastPoint = event->pos();
+        scribbling = true;
+    }
+}
+
+// When the mouse moves if the left button is clicked
+// we call the drawline function which draws a line
+// from the last position to the current
+void ScribbleArea::mouseMoveEvent(QMouseEvent *event)
+{
+    if ((event->buttons() & Qt::LeftButton) && scribbling)
+        drawLineTo(event->pos());
+}
+
+// If the button is released we set variables to stop drawing
+void ScribbleArea::mouseReleaseEvent(QMouseEvent *event)
+{
+    if (event->button() == Qt::LeftButton && scribbling) {
+        drawLineTo(event->pos());
+        scribbling = false;
+    }
+}
+
+// QPainter provides functions to draw on the widget
+// The QPaintEvent is sent to widgets that need to
+// update themselves
+void ScribbleArea::paintEvent(QPaintEvent *event)
+{
+    QPainter painter(this);
+
+    // Returns the rectangle that needs to be updated
+    QRect dirtyRect = event->rect();
+
+    // Draws the rectangle where the image needs to
+    // be updated
+    painter.drawImage(dirtyRect, image, dirtyRect);
+}
+
+// Resize the image to slightly larger then the main window
+// to cut down on the need to resize the image
+void ScribbleArea::resizeEvent(QResizeEvent *event)
+{
+    if (width() > image.width() || height() > image.height()) {
+        int newWidth = qMax(width() + 128, image.width());
+        int newHeight = qMax(height() + 128, image.height());
+        resizeImage(&image, QSize(newWidth, newHeight));
+        update();
+    }
+    QWidget::resizeEvent(event);
+}
+
+void ScribbleArea::drawLineTo(const QPoint &endPoint)
+{
+    // Used to draw on the widget
+    QPainter painter(&image);
+
+    // Set the current settings for the pen
+    painter.setPen(QPen(myPenColor, myPenWidth, Qt::SolidLine, Qt::RoundCap,
+                        Qt::RoundJoin));
+
+    // Draw a line from the last registered point to the current
+    painter.drawLine(lastPoint, endPoint);
+
+    // Set that the image hasn't been saved
+    modified = true;
+
+    int rad = (myPenWidth / 2) + 2;
+
+    // Call to update the rectangular space where we drew
+    update(QRect(lastPoint, endPoint).normalized()
+                                     .adjusted(-rad, -rad, +rad, +rad));
+
+    // Update the last position where we left off drawing
+    lastPoint = endPoint;
+}
+
+// When the app is resized create a new image using
+// the changes made to the image
+void ScribbleArea::resizeImage(QImage *image, const QSize &newSize)
+{
+    // Check if we need to redraw the image
+    if (image->size() == newSize)
+        return;
+
+    // Create a new image to display and fill it with white
+    QImage newImage(newSize, QImage::Format_RGB32);
+    newImage.fill(qRgb(255, 255, 255));
+
+    // Draw the image
+    QPainter painter(&newImage);
+    painter.drawImage(QPoint(0, 0), *image);
+    *image = newImage;
+}
+