Add sky grid painting

imagewidget.h

@@ -8,6 +8,7 @@
 #include <QOpenGLTexture>
 #include <QOpenGLVertexArrayObject>
 #include <QOpenGLFunctions>
+#include <QPainterPath>
 #include "database.h"
 #include "rawimage.h"
 #include "imageinfodata.h"
@@ -37,6 +38,7 @@ public:
     virtual QImage renderToImage() = 0;
     virtual void thumbnailLoaded(const Image *image) = 0;
     virtual void showThumbnail(bool enable) = 0;
+    virtual void drawGrid(bool enable) = 0;
 
     static QImage loadColormap();
 };
@@ -70,6 +72,8 @@ class ImageWidgetGL : public QOpenGLWidget, public ImageWidget
     GLuint m_debayerTex = 0;
     std::shared_ptr<RawImage> m_rawImage;
     std::shared_ptr<WCSDataT> m_wcs;
+    QPainterPath m_grid;
+    QPainterPath m_text;
     int m_width, m_height;
     int m_imgWidth = -1, m_imgHeight = -1;
     int m_currentImg = 0;
@@ -87,6 +91,7 @@ class ImageWidgetGL : public QOpenGLWidget, public ImageWidget
     bool m_selecting = false;
     bool m_sizesDirty = false;
     bool m_srgb = false;
+    bool m_drawGrid = false;
     int m_thumbnailCount = 0;
     int m_maxTextureSize = 0;
     int m_maxArrayLayers = 0;
@@ -116,6 +121,7 @@ public:
     QImage renderToImage() override;
     void thumbnailLoaded(const Image *image) override;
     void showThumbnail(bool enable) override;
+    void drawGrid(bool enable) override;
 protected:
     void paintGL() override;
     void resizeGL(int w, int h) override;