![](https://img.laitimes.com/img/__Qf2AjLwojIjJCLyojI0JCLicmbw5CMmJDMzM2NwMWO2UmYlFDZwkjNmZGO0MWMmJTZiVDZm9CX0JXZ252bj91Ztl2Lc52YucWbp5GZzNmLn9Gbi1yZtl2Lc9CX6MHc0RHaiojIsJye.png)
需求:
在界面上點選“顯示圖檔”按鈕,會調用scrollarea視窗顯示圖檔,視窗大小能根據圖檔大小自動調整,但是最大為1024*768,圖檔過大就要有滾動條來顯示
IDE環境:
QT Creator ,linux ,ubuntu12.04
代碼:
mainwindow中點選“顯示圖檔”調用scrollarea視窗,下面的函數是被一個按鈕的槽函數調用的
void MainWindow::Show_Image_byname(char *filename){ if(!filename || !strlen(filename)) { return; } char buf[128]= {0}; strcpy(buf,SAVE_IMAGE); strcat(buf,filename); ScrollArea *new_image = new ScrollArea(); new_image->set_image(buf); new_image->setBackgroundRole(QPalette::Dark); new_image->show(); return;}
添加檔案scrollarea.ui檔案,畫出一個scrollarea
在生成的scrollarea.h中添加私有成員QLabel
private: Ui::ScrollArea *ui; QLabel * label;
在析構函數中添加記憶體釋放
ScrollArea::~ScrollArea(){ delete ui; if(label) { delete label; }}
在生成的scrollarea.cpp中添加圖檔顯示實作函數
void ScrollArea::set_image(char *filename){ QImage *ppm = new QImage(filename); label = new QLabel(); printf("ppm->width()=%d, ppm->height()=%d",ppm->width(), ppm->height()); //擷取圖檔的寬度和高度 label->setPixmap(QPixmap::fromImage(*ppm)); this->setWidget(label); /*設定視窗最大高度和寬度為1024*768*/ this->setMaximumHeight(768); this->setMaximumWidth(1024); this->resize(QSize( ppm->width()+5, ppm->height() +5)); return;}