子类化QWidget

源码:

iconeditor.h

#ifndef ICONEDITOR_H

#define ICONEDITOR_H



#include <QColor>

#include <QImage>

#include <QWidget>



class IconEditor : public QWidget

{

    Q_OBJECT


  //Q_PROPERTY()宏来设置属性
Q_PROPERTY(QColor penColor READ penColor WRITE setPenColor) Q_PROPERTY(QImage iconImage READ iconImage WRITE setIconImage) Q_PROPERTY(
int zoomFactor READ zoomFactor WRITE setZoomFactor) public: IconEditor(QWidget *parent = 0); void setPenColor(const QColor &newColor); QColor penColor() const { return curColor; } void setZoomFactor(int newZoom); int zoomFactor() const { return zoom; } void setIconImage(const QImage &newImage); QImage iconImage() const { return image; } QSize sizeHint() const; protected: void mousePressEvent(QMouseEvent *event); void mouseMoveEvent(QMouseEvent *event); void paintEvent(QPaintEvent *event); private: void setImagePixel(const QPoint &pos, bool opaque); QRect pixelRect(int i, int j) const; QColor curColor; QImage image; int zoom; }; #endif

 iconeditor.cpp

#include <QtGui>



#include "iconeditor.h"



IconEditor::IconEditor(QWidget *parent)

    : QWidget(parent)

{

    setAttribute(Qt::WA_StaticContents);

    setSizePolicy(QSizePolicy::Minimum, QSizePolicy::Minimum);



    curColor = Qt::black;

    zoom = 8;  //缩放因子

    image = QImage(16, 16, QImage::Format_ARGB32);   //16*16的像素大小和32位的ARGB
    image.fill(qRgba(
0, 0, 0, 0)); } void IconEditor::setPenColor(const QColor &newColor) { curColor = newColor; } void IconEditor::setZoomFactor(int newZoom) { if (newZoom < 1) newZoom = 1; if (newZoom != zoom) { zoom = newZoom; update(); updateGeometry(); } } void IconEditor::setIconImage(const QImage &newImage) { if (newImage != image) { image = newImage.convertToFormat(QImage::Format_ARGB32); update(); updateGeometry(); } } QSize IconEditor::sizeHint() const { QSize size = zoom * image.size(); if (zoom >= 3) size += QSize(1, 1); return size; } void IconEditor::mousePressEvent(QMouseEvent *event) { if (event->button() == Qt::LeftButton) { setImagePixel(event->pos(), true); } else if (event->button() == Qt::RightButton) { setImagePixel(event->pos(), false); } } void IconEditor::mouseMoveEvent(QMouseEvent *event) { if (event->buttons() & Qt::LeftButton) { setImagePixel(event->pos(), true); } else if (event->buttons() & Qt::RightButton) { setImagePixel(event->pos(), false); } } void IconEditor::paintEvent(QPaintEvent *event) { QPainter painter(this); if (zoom >= 3) { painter.setPen(palette().foreground().color()); for (int i = 0; i <= image.width(); ++i) painter.drawLine(zoom * i, 0, zoom * i, zoom * image.height()); for (int j = 0; j <= image.height(); ++j) painter.drawLine(0, zoom * j, zoom * image.width(), zoom * j); } for (int i = 0; i < image.width(); ++i) { for (int j = 0; j < image.height(); ++j) { QRect rect = pixelRect(i, j); if (!event->region().intersect(rect).isEmpty()) { QColor color = QColor::fromRgba(image.pixel(i, j)); if (color.alpha() < 255) painter.fillRect(rect, Qt::white); painter.fillRect(rect, color); } } } } void IconEditor::setImagePixel(const QPoint &pos, bool opaque) { int i = pos.x() / zoom; int j = pos.y() / zoom; if (image.rect().contains(i, j)) { if (opaque) { image.setPixel(i, j, penColor().rgba()); } else { image.setPixel(i, j, qRgba(0, 0, 0, 0)); } update(pixelRect(i, j)); } } QRect IconEditor::pixelRect(int i, int j) const { if (zoom >= 3) { return QRect(zoom * i + 1, zoom * j + 1, zoom - 1, zoom - 1); } else { return QRect(zoom * i, zoom * j, zoom, zoom); } }

main.c

#include <QApplication>



#include "iconeditor.h"



int main(int argc, char *argv[])

{

    QApplication app(argc, argv);

    IconEditor iconEditor;

    iconEditor.setWindowTitle(QObject::tr("Icon Editor"));

    iconEditor.setIconImage(QImage(":/images/mouse.png"));

    iconEditor.show();

    return app.exec();

}

 

附加小知识:

1:一个具有32位色深的图像分别对每一个像素各使用8位来存储它的红绿蓝分量,剩余的8位存储这个像素的alpha分量(即不透明度)

  如: QRgb red = qRgba(255, 0,0,255);  或 QRgb red = 0xFFFF0000;

2:Qt提供来俩种存储颜色的类型:QRgb和QColor

3:QPainter::drawLine() 例:painter.drawLine(x1,y1,x2,y2);

4:每一个窗口部件都会配备一个调色板,由它来确定做什么事应该使用什么颜色

5:QWidget::palette()函数可用返回窗口部件的调色板,它是一个QPalette型对象

6:QRect(x ,y , width, height);

 

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