From 26be690c70e55a4a8aed7a95334dbd757de28e2a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Du=C5=A1an=20Poizl?= <nou.spiro@gmail.com>
Date: Thu, 14 Apr 2022 11:20:16 +0200
Subject: [PATCH] Add drop file support

---
 imagescrollareagl.cpp | 25 +++++++++++++++++++++++++
 imagescrollareagl.h   |  4 ++++
 mainwindow.cpp        |  3 ++-
 mainwindow.h          |  2 +-
 4 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/imagescrollareagl.cpp b/imagescrollareagl.cpp
index d76564b..a162efd 100644
--- a/imagescrollareagl.cpp
+++ b/imagescrollareagl.cpp
@@ -6,6 +6,7 @@
 #include <QOpenGLPixelTransferOptions>
 #include <QOpenGLFramebufferObject>
 #include <QGridLayout>
+#include <QMimeData>
 
 struct RawImageType
 {
@@ -54,6 +55,7 @@ ImageWidget::ImageWidget(QWidget *parent) : QOpenGLWidget(parent)
     m_range = UINT16_MAX;
     m_imgWidth = m_imgHeight = -1;
     m_superpixel = m_invert = false;
+    setAcceptDrops(true);
 }
 
 ImageWidget::~ImageWidget()
@@ -256,6 +258,29 @@ void ImageWidget::initializeGL()
     m_transferOptions->setAlignment(1);
 }
 
+void ImageWidget::dragEnterEvent(QDragEnterEvent *event)
+{
+    if(event->mimeData()->hasUrls() && event->proposedAction() & (Qt::CopyAction | Qt::MoveAction))
+        event->acceptProposedAction();
+}
+
+void ImageWidget::dropEvent(QDropEvent *event)
+{
+    if(event->mimeData()->hasUrls() && event->proposedAction() & (Qt::CopyAction | Qt::MoveAction))
+    {
+        for(const QUrl &url : event->mimeData()->urls())
+        {
+            if(url.isLocalFile())
+            {
+                emit fileDropped(url.path());
+                event->accept();
+                return;
+            }
+        }
+    }
+    event->ignore();
+}
+
 ImageScrollAreaGL::ImageScrollAreaGL(QWidget *parent) : QWidget(parent)
 {
     QGridLayout *layout = new QGridLayout(this);
diff --git a/imagescrollareagl.h b/imagescrollareagl.h
index 686afca..2eb7363 100644
--- a/imagescrollareagl.h
+++ b/imagescrollareagl.h
@@ -59,6 +59,10 @@ protected:
     void paintGL();
     void resizeGL(int w, int h);
     void initializeGL();
+    void dragEnterEvent(QDragEnterEvent *event);
+    void dropEvent(QDropEvent *event);
+signals:
+    void fileDropped(const QString &path);
 };
 
 class ImageScrollAreaGL : public QWidget
diff --git a/mainwindow.cpp b/mainwindow.cpp
index 7d9d9b1..c663bd0 100644
--- a/mainwindow.cpp
+++ b/mainwindow.cpp
@@ -80,6 +80,7 @@ MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent)
     connect(m_ringList, SIGNAL(currentImageChanged(int)), this, SLOT(updateWindowTitle()));
     connect(m_ringList, SIGNAL(infoLoaded(ImageInfoData)), m_info, SLOT(setInfo(const ImageInfoData&)));
     connect(m_ringList, SIGNAL(currentImageChanged(int)), m_filesystem, SLOT(selectFile(int)));
+    connect(m_imageGL->imageWidget(), &ImageWidget::fileDropped, this, static_cast<void (MainWindow::*)(const QString &)>(&MainWindow::loadFile));
 
     QMenu *fileMenu = new QMenu(tr("File"), this);
     fileMenu->addAction(tr("Open"), this, SLOT(loadFile()), QKeySequence("Ctrl+O"));
@@ -256,7 +257,7 @@ void MainWindow::loadFile()
     loadFile(file);
 }
 
-void MainWindow::loadFile(const QString path)
+void MainWindow::loadFile(const QString &path)
 {
     if(!path.isEmpty())
     {
diff --git a/mainwindow.h b/mainwindow.h
index c9a83e6..1c81e3d 100644
--- a/mainwindow.h
+++ b/mainwindow.h
@@ -41,7 +41,7 @@ protected slots:
     void updateWindowTitle();
     void pixmapLoaded(Image *image);
     void loadFile();
-    void loadFile(const QString path);
+    void loadFile(const QString &path);
     void loadFile(int row);
     void indexDir();
     void saveAs();