qtmips_gui/graphicsview.cpp


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#include "graphicsview.h"

GraphicsView::GraphicsView(QWidget *parent) : QGraphicsView(parent) {
    setRenderHints(QPainter::Antialiasing | QPainter::SmoothPixmapTransform);
}

void GraphicsView::setScene(QGraphicsScene *scene) {
    QGraphicsView::setScene(scene);
    update_scale();
}

void GraphicsView::resizeEvent(QResizeEvent *event) {
    QGraphicsView::resizeEvent(event);
    update_scale();
}

void GraphicsView::update_scale() {
    if (scene() == nullptr)
        return; // Skip if we have no scene

    // Note: there is somehow three pixels error when viewing so we have to always compensate
    const int w = scene()->width() + 3;
    const int h = scene()->height() + 3;

    qreal scale = 1;
    if (height() > h && width() > w) {
        if (height() > width()) {
            scale = (qreal)width() / w;
        } else {
            scale = (qreal)height() / h;
        }
    }
    QTransform t;
    t.scale(scale, scale);
    setTransform(t, false);
}