49 lines
1.2 KiB
C++
49 lines
1.2 KiB
C++
#include "BrushPad.h"
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#include <QPainter>
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#include <QPaintEvent>
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#include <QDebug>
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BrushPad::BrushPad(QWidget *parent)
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: QGroupBox(parent)
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{
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setMinimumSize(100, 100);
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m_canvas = QPixmap(size());
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m_canvas.fill(Qt::transparent);
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}
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void BrushPad::setBrushImage(const QImage &img)
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{
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m_brush = img.convertToFormat(QImage::Format_ARGB32_Premultiplied);
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}
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void BrushPad::moveBrush(const QPoint &globalPos)
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{
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// 1. 不管笔刷图，直接画一个 20×20 的红色方块到指定坐标
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QPainter p(&m_canvas);
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p.setCompositionMode(QPainter::CompositionMode_SourceOver);
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p.drawImage(globalPos, m_brush); // 直接叠加，不清屏
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update();
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}
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void BrushPad::paintEvent(QPaintEvent *)
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{
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// 让基类画边框/标题
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QGroupBox::paintEvent(nullptr);
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// 直接把我们自己的画布贴出来
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QPainter p(this);
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p.drawPixmap(contentsRect().topLeft(), m_canvas);
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// 这里 **绝对不要再调用 update()/repaint()**
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}
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void BrushPad::resizeEvent(QResizeEvent *)
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{
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// 画布跟随控件大小
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QPixmap newPix(contentsRect().size());
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newPix.fill(Qt::transparent);
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QPainter p(&newPix);
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p.drawPixmap(0, 0, m_canvas);
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m_canvas = newPix;
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}
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