Add setting to have GAL draw axes on the grid

common/gal/cairo/cairo_gal.cpp

@@ -87,6 +87,7 @@ CAIRO_GAL::CAIRO_GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions,
 
     // Grid color settings are different in Cairo and OpenGL
     SetGridColor( COLOR4D( 0.1, 0.1, 0.1, 0.8 ) );
+    SetAxesColor( COLOR4D( BLUE ) );
 
     // Allocate memory for pixel storage
     allocateBitmaps();
@@ -819,7 +820,7 @@ void CAIRO_GAL::drawGridLine( const VECTOR2D& aStartPoint, const VECTOR2D& aEndP
 {
     cairo_move_to( currentContext, aStartPoint.x, aStartPoint.y );
     cairo_line_to( currentContext, aEndPoint.x, aEndPoint.y );
-    cairo_set_source_rgba( currentContext, gridColor.r, gridColor.g, gridColor.b, strokeColor.a );
+    cairo_set_source_rgba( currentContext, strokeColor.r, strokeColor.g, strokeColor.b, strokeColor.a );
     cairo_stroke( currentContext );
 }
 

common/gal/gal_display_options.cpp

@@ -35,6 +35,7 @@ static const wxString GalGLAntialiasingKeyword( "OpenGLAntialiasingMode" );
 static const wxString GalGridStyleConfig( "GridStyle" );
 static const wxString GalGridLineWidthConfig( "GridLineWidth" );
 static const wxString GalGridMaxDensityConfig( "GridMaxDensity" );
+static const wxString GalGridAxesEnabledConfig( "GridAxesEnabled" );
 
 
 static const UTIL::CFG_MAP<KIGFX::OPENGL_ANTIALIASING_MODE> aaModeConfigVals =
@@ -57,7 +58,10 @@ static const UTIL::CFG_MAP<KIGFX::GRID_STYLE> gridStyleConfigVals =
 
 GAL_DISPLAY_OPTIONS::GAL_DISPLAY_OPTIONS()
     : gl_antialiasing_mode( OPENGL_ANTIALIASING_MODE::NONE ),
-      m_gridStyle( GRID_STYLE::DOTS )
+      m_gridStyle( GRID_STYLE::DOTS ),
+      m_gridLineWidth( 0.5 ),
+      m_gridMinSpacing( 10 ),
+      m_axesEnabled( false )
 {}
 
 
@@ -79,6 +83,9 @@ void GAL_DISPLAY_OPTIONS::ReadConfig( wxConfigBase* aCfg, wxString aBaseName )
     aCfg->Read( aBaseName + GalGridMaxDensityConfig,
                 &m_gridMinSpacing, 10 );
 
+    aCfg->Read( aBaseName + GalGridAxesEnabledConfig,
+                &m_axesEnabled, false );
+
     NotifyChanged();
 }
 
@@ -96,6 +103,9 @@ void GAL_DISPLAY_OPTIONS::WriteConfig( wxConfigBase* aCfg, wxString aBaseName )
 
     aCfg->Write( aBaseName + GalGridMaxDensityConfig,
                  m_gridMinSpacing );
+
+    aCfg->Write( aBaseName + GalGridAxesEnabledConfig,
+                 m_axesEnabled );
 }
 
 

common/gal/graphics_abstraction_layer.cpp

@@ -110,6 +110,12 @@ bool GAL::updatedGalDisplayOptions( const GAL_DISPLAY_OPTIONS& aOptions )
         refresh = true;
     }
 
+    if( options.m_axesEnabled != axesEnabled )
+    {
+        axesEnabled = options.m_axesEnabled;
+        refresh = true;
+    }
+
     // tell the derived class if the base class needs an update or not
     return refresh;
 }
@@ -335,6 +341,21 @@ void GAL::DrawGrid()
             }
         }
     }
+
+    // Draw axes if desired
+    if( axesEnabled )
+    {
+        SetIsFill( false );
+        SetIsStroke( true );
+        SetStrokeColor( axesColor );
+        SetLineWidth( marker );
+
+        drawGridLine( VECTOR2D( worldStartPoint.x, 0 ),
+                      VECTOR2D( worldEndPoint.x, 0 ) );
+
+        drawGridLine( VECTOR2D( 0, worldStartPoint.y ),
+                      VECTOR2D( 0, worldEndPoint.y ) );
+    }
 }
 
 

common/gal/opengl/opengl_gal.cpp

@@ -129,6 +129,7 @@ OPENGL_GAL::OPENGL_GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions, wxWindow* aParent,
 
     // Grid color settings are different in Cairo and OpenGL
     SetGridColor( COLOR4D( 0.8, 0.8, 0.8, 0.1 ) );
+    SetAxesColor( COLOR4D( BLUE ) );
 
     // Tesselator initialization
     tesselator = gluNewTess();
@@ -994,6 +995,23 @@ void OPENGL_GAL::DrawGrid()
             glDisable( GL_STENCIL_TEST );
     }
 
+    // Draw axes if desired
+    if( axesEnabled )
+    {
+        glLineWidth( minorLineWidth );
+        glColor4d( axesColor.r, axesColor.g, axesColor.b, 1.0 );
+
+        glBegin( GL_LINES );
+        glVertex2d( worldStartPoint.x, 0 );
+        glVertex2d( worldEndPoint.x, 0 );
+        glEnd();
+
+        glBegin( GL_LINES );
+        glVertex2d( 0, worldStartPoint.y );
+        glVertex2d( 0, worldEndPoint.y );
+        glEnd();
+    }
+
     glEnable( GL_DEPTH_TEST );
     glEnable( GL_TEXTURE_2D );
 }

include/gal/gal_display_options.h

@@ -81,6 +81,9 @@ namespace KIGFX
 
         ///> Minimum pixel distance between displayed grid lines
         double m_gridMinSpacing;
+
+        ///> Whether or not to draw the coordinate system axes
+        bool m_axesEnabled;
     };
 
 }

include/gal/graphics_abstraction_layer.h

@@ -799,6 +799,16 @@ public:
         gridColor = aGridColor;
     }
 
+    /**
+     * @brief Set the axes color.
+     *
+     * @param aAxesColor is the color to draw the axes if enabled.
+     */
+    inline void SetAxesColor( const COLOR4D& aAxesColor )
+    {
+        axesColor = aAxesColor;
+    }
+
     /**
      * @brief Draw every tick line wider.
      *
@@ -975,6 +985,8 @@ protected:
     VECTOR2D           gridOrigin;             ///< The grid origin
     VECTOR2D           gridOffset;             ///< The grid offset to compensate cursor position
     COLOR4D            gridColor;              ///< Color of the grid
+    COLOR4D            axesColor;              ///< Color of the axes
+    bool               axesEnabled;            ///< Should the axes be drawn
     int                gridTick;               ///< Every tick line gets the double width
     double             gridLineWidth;          ///< Line width of the grid
     int                gridMinSpacing;         ///< Minimum screen size of the grid (pixels)