cairo_gal.cpp

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/*
 * This program source code file is part of KICAD, a free EDA CAD application.
 *
 * Copyright (C) 2012 Torsten Hueter, torstenhtr <at> gmx.de
 * Copyright (C) 2012-2021 Kicad Developers, see AUTHORS.txt for contributors.
 * Copyright (C) 2017-2018 CERN
 *
 * @author Maciej Suminski <[email protected]>
 *
 * CairoGal - Graphics Abstraction Layer for Cairo
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, you may find one here:
 * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
 * or you may search the http://www.gnu.org website for the version 2 license,
 * or you may write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <wx/image.h>
#include <wx/log.h>

#include <gal/cairo/cairo_gal.h>
#include <gal/cairo/cairo_compositor.h>
#include <gal/definitions.h>
#include <geometry/shape_poly_set.h>
#include <math/util.h> // for KiROUND
#include <bitmap_base.h>

#include <algorithm>
#include <cmath>
#include <limits>

#include <pixman.h>

using namespace KIGFX;


CAIRO_GAL_BASE::CAIRO_GAL_BASE( GAL_DISPLAY_OPTIONS& aDisplayOptions ) : GAL( aDisplayOptions )
{
 // Initialise grouping
 m_isGrouping = false;
 m_isElementAdded = false;
 m_groupCounter = 0;
 m_currentGroup = nullptr;

 m_lineWidth = 1.0;
 m_lineWidthInPixels = 1.0;
 m_lineWidthIsOdd = true;

 // Initialise Cairo state
 cairo_matrix_init_identity( &m_cairoWorldScreenMatrix );
 m_currentContext = nullptr;
 m_context = nullptr;
 m_surface = nullptr;

 // Grid color settings are different in Cairo and OpenGL
 SetGridColor( COLOR4D( 0.1, 0.1, 0.1, 0.8 ) );
 SetAxesColor( COLOR4D( BLUE ) );

 // Avoid uninitialized variables:
 cairo_matrix_init_identity( &m_currentXform );
 cairo_matrix_init_identity( &m_currentWorld2Screen );
}


CAIRO_GAL_BASE::~CAIRO_GAL_BASE()
{
 ClearCache();

 if( m_surface )
 cairo_surface_destroy( m_surface );

 if( m_context )
 cairo_destroy( m_context );

 for( _cairo_surface* imageSurface : m_imageSurfaces )
 cairo_surface_destroy( imageSurface );
}


void CAIRO_GAL_BASE::BeginDrawing()
{
 resetContext();
}


void CAIRO_GAL_BASE::EndDrawing()
{
 // Force remaining objects to be drawn
 Flush();
}


void CAIRO_GAL_BASE::updateWorldScreenMatrix()
{
 cairo_matrix_multiply( &m_currentWorld2Screen, &m_currentXform, &m_cairoWorldScreenMatrix );
}


const VECTOR2D CAIRO_GAL_BASE::xform( double x, double y )
{
 VECTOR2D rv;

 rv.x = m_currentWorld2Screen.xx * x + m_currentWorld2Screen.xy * y + m_currentWorld2Screen.x0;
 rv.y = m_currentWorld2Screen.yx * x + m_currentWorld2Screen.yy * y + m_currentWorld2Screen.y0;
 return rv;
}


const VECTOR2D CAIRO_GAL_BASE::xform( const VECTOR2D& aP )
{
 return xform( aP.x, aP.y );
}


const double CAIRO_GAL_BASE::angle_xform( const double aAngle )
{
 // calculate rotation angle due to the rotation transform
 // and if flipped on X axis.
 double world_rotation = -std::atan2( m_currentWorld2Screen.xy, m_currentWorld2Screen.xx );

 // When flipped on X axis, the rotation angle is M_PI - initial angle:
 if( IsFlippedX() )
 world_rotation = M_PI - world_rotation;

 return std::fmod( aAngle + world_rotation, 2.0 * M_PI );
}


void CAIRO_GAL_BASE::arc_angles_xform_and_normalize( double& aStartAngle, double& aEndAngle )
{
 // 360 deg arcs have a specific calculation.
 bool is_360deg_arc = std::abs( aEndAngle - aStartAngle ) >= 2 * M_PI;
 double startAngle = aStartAngle;
 double endAngle = aEndAngle;

 // When the view is flipped, the coordinates are flipped by the matrix transform
 // However, arc angles need to be "flipped": the flipped angle is M_PI - initial angle.
 if( IsFlippedX() )
 {
 startAngle = M_PI - startAngle;
 endAngle = M_PI - endAngle;
 }

 // Normalize arc angles
 SWAP( startAngle, >, endAngle );

 // now rotate arc according to the rotation transform matrix
 // Remark:
 // We call angle_xform() to calculate angles according to the flip/rotation
 // transform and normalize between -2M_PI and +2M_PI.
 // Therefore, if aStartAngle = aEndAngle + 2*n*M_PI, the transform gives
 // aEndAngle = aStartAngle
 // So, if this is the case, force the aEndAngle value to draw a circle.
 aStartAngle = angle_xform( startAngle );

 if( is_360deg_arc ) // arc is a full circle
 aEndAngle = aStartAngle + 2 * M_PI;
 else
 aEndAngle = angle_xform( endAngle );
}


const double CAIRO_GAL_BASE::xform( double x )
{
 double dx = m_currentWorld2Screen.xx * x;
 double dy = m_currentWorld2Screen.yx * x;
 return sqrt( dx * dx + dy * dy );
}


static double roundp( double x )
{
 return floor( x + 0.5 ) + 0.5;
}


const VECTOR2D CAIRO_GAL_BASE::roundp( const VECTOR2D& v )
{
 if( m_lineWidthIsOdd && m_isStrokeEnabled )
 return VECTOR2D( ::roundp( v.x ), ::roundp( v.y ) );
 else
 return VECTOR2D( floor( v.x + 0.5 ), floor( v.y + 0.5 ) );
}


void CAIRO_GAL_BASE::DrawLine( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint )
{
 syncLineWidth();

 VECTOR2D p0 = roundp( xform( aStartPoint ) );
 VECTOR2D p1 = roundp( xform( aEndPoint ) );

 cairo_move_to( m_currentContext, p0.x, p0.y );
 cairo_line_to( m_currentContext, p1.x, p1.y );
 flushPath();
 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::syncLineWidth( bool aForceWidth, double aWidth )
{
 double w = floor( xform( aForceWidth ? aWidth : m_lineWidth ) + 0.5 );

 if( w <= 1.0 )
 {
 w = 1.0;
 cairo_set_line_join( m_currentContext, CAIRO_LINE_JOIN_MITER );
 cairo_set_line_cap( m_currentContext, CAIRO_LINE_CAP_BUTT );
 cairo_set_line_width( m_currentContext, 1.0 );
 m_lineWidthIsOdd = true;
 }
 else
 {
 cairo_set_line_join( m_currentContext, CAIRO_LINE_JOIN_ROUND );
 cairo_set_line_cap( m_currentContext, CAIRO_LINE_CAP_ROUND );
 cairo_set_line_width( m_currentContext, w );
 m_lineWidthIsOdd = ( (int) w % 2 ) == 1;
 }

 m_lineWidthInPixels = w;
}


void CAIRO_GAL_BASE::DrawSegment( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint,
 double aWidth )
{
 if( m_isFillEnabled )
 {
 syncLineWidth( true, aWidth );

 VECTOR2D p0 = roundp( xform( aStartPoint ) );
 VECTOR2D p1 = roundp( xform( aEndPoint ) );

 cairo_move_to( m_currentContext, p0.x, p0.y );
 cairo_line_to( m_currentContext, p1.x, p1.y );
 cairo_set_source_rgba( m_currentContext, m_fillColor.r, m_fillColor.g, m_fillColor.b,
 m_fillColor.a );
 cairo_stroke( m_currentContext );
 }
 else
 {
 aWidth /= 2.0;
 SetLineWidth( 1.0 );
 syncLineWidth();

 // Outline mode for tracks
 VECTOR2D startEndVector = aEndPoint - aStartPoint;
 double lineAngle = atan2( startEndVector.y, startEndVector.x );

 double sa = sin( lineAngle + M_PI / 2.0 );
 double ca = cos( lineAngle + M_PI / 2.0 );

 VECTOR2D pa0 = xform( aStartPoint + VECTOR2D( aWidth * ca, aWidth * sa ) );
 VECTOR2D pa1 = xform( aStartPoint - VECTOR2D( aWidth * ca, aWidth * sa ) );
 VECTOR2D pb0 = xform( aEndPoint + VECTOR2D( aWidth * ca, aWidth * sa ) );
 VECTOR2D pb1 = xform( aEndPoint - VECTOR2D( aWidth * ca, aWidth * sa ) );

 cairo_set_source_rgba( m_currentContext, m_strokeColor.r, m_strokeColor.g, m_strokeColor.b,
 m_strokeColor.a );

 cairo_move_to( m_currentContext, pa0.x, pa0.y );
 cairo_line_to( m_currentContext, pb0.x, pb0.y );

 cairo_move_to( m_currentContext, pa1.x, pa1.y );
 cairo_line_to( m_currentContext, pb1.x, pb1.y );
 flushPath();

 // Calculate the segment angle and arc center in normal/mirrored transform for rounded ends.
 VECTOR2D center_a = xform( aStartPoint );
 VECTOR2D center_b = xform( aEndPoint );
 startEndVector = center_b - center_a;
 lineAngle = atan2( startEndVector.y, startEndVector.x );
 double radius = ( pa0 - center_a ).EuclideanNorm();

 // Draw the rounded end point of the segment
 double arcStartAngle = lineAngle - M_PI / 2.0;
 cairo_arc( m_currentContext, center_b.x, center_b.y, radius, arcStartAngle, arcStartAngle + M_PI );

 // Draw the rounded start point of the segment
 arcStartAngle = lineAngle + M_PI / 2.0;
 cairo_arc( m_currentContext, center_a.x, center_a.y, radius, arcStartAngle, arcStartAngle + M_PI );

 flushPath();
 }

 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::DrawCircle( const VECTOR2D& aCenterPoint, double aRadius )
{
 syncLineWidth();

 VECTOR2D c = roundp( xform( aCenterPoint ) );
 double r = ::roundp( xform( aRadius ) );

 cairo_set_line_width( m_currentContext, std::min( 2.0 * r, m_lineWidthInPixels ) );
 cairo_new_sub_path( m_currentContext );
 cairo_arc( m_currentContext, c.x, c.y, r, 0.0, 2 * M_PI );
 cairo_close_path( m_currentContext );
 flushPath();
 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::DrawArc( const VECTOR2D& aCenterPoint, double aRadius, double aStartAngle,
 double aEndAngle )
{
 syncLineWidth();

 // calculate start and end arc angles according to the rotation transform matrix
 // and normalize:
 arc_angles_xform_and_normalize( aStartAngle, aEndAngle );

 double r = xform( aRadius );

 // N.B. This is backwards. We set this because we want to adjust the center
 // point that changes both endpoints. In the worst case, this is twice as far.
 // We cannot adjust radius or center based on the other because this causes the
 // whole arc to change position/size
 m_lineWidthIsOdd = !( static_cast<int>( aRadius ) % 2 );

 auto mid = roundp( xform( aCenterPoint ) );

 cairo_set_line_width( m_currentContext, m_lineWidthInPixels );
 cairo_new_sub_path( m_currentContext );

 if( m_isFillEnabled )
 cairo_move_to( m_currentContext, mid.x, mid.y );

 cairo_arc( m_currentContext, mid.x, mid.y, r, aStartAngle, aEndAngle );

 if( m_isFillEnabled )
 cairo_close_path( m_currentContext );

 flushPath();

 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::DrawArcSegment( const VECTOR2D& aCenterPoint, double aRadius,
 double aStartAngle, double aEndAngle, double aWidth,
 double aMaxError )
{
 // Note: aMaxError is not used because Cairo can draw true arcs
 if( m_isFillEnabled )
 {
 m_lineWidth = aWidth;
 m_isStrokeEnabled = true;
 m_isFillEnabled = false;
 DrawArc( aCenterPoint, aRadius, aStartAngle, aEndAngle );
 m_isFillEnabled = true;
 m_isStrokeEnabled = false;
 return;
 }

 syncLineWidth();

 // calculate start and end arc angles according to the rotation transform matrix
 // and normalize:
 double startAngleS = aStartAngle;
 double endAngleS = aEndAngle;
 arc_angles_xform_and_normalize( startAngleS, endAngleS );

 double r = xform( aRadius );

 // N.B. This is backwards. We set this because we want to adjust the center
 // point that changes both endpoints. In the worst case, this is twice as far.
 // We cannot adjust radius or center based on the other because this causes the
 // whole arc to change position/size
 m_lineWidthIsOdd = !( static_cast<int>( aRadius ) % 2 );

 VECTOR2D mid = roundp( xform( aCenterPoint ) );
 double width = xform( aWidth / 2.0 );
 VECTOR2D startPointS = VECTOR2D( r, 0.0 ).Rotate( startAngleS );
 VECTOR2D endPointS = VECTOR2D( r, 0.0 ).Rotate( endAngleS );

 cairo_save( m_currentContext );

 cairo_set_source_rgba( m_currentContext, m_strokeColor.r, m_strokeColor.g, m_strokeColor.b,
 m_strokeColor.a );

 cairo_translate( m_currentContext, mid.x, mid.y );

 cairo_new_sub_path( m_currentContext );
  cairo_arc( m_currentContext, 0, 0, r - width, startAngleS, endAngleS );

 cairo_new_sub_path( m_currentContext );
 cairo_arc( m_currentContext, 0, 0, r + width, startAngleS, endAngleS );

 cairo_new_sub_path( m_currentContext );
 cairo_arc_negative( m_currentContext, startPointS.x, startPointS.y, width, startAngleS,
 startAngleS + M_PI );

 cairo_new_sub_path( m_currentContext );
 cairo_arc( m_currentContext, endPointS.x, endPointS.y, width, endAngleS, endAngleS + M_PI );

 cairo_restore( m_currentContext );
 flushPath();

 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::DrawRectangle( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint )
{
 // Calculate the diagonal points
 syncLineWidth();

 const VECTOR2D p0 = roundp( xform( aStartPoint ) );
 const VECTOR2D p1 = roundp( xform( VECTOR2D( aEndPoint.x, aStartPoint.y ) ) );
 const VECTOR2D p2 = roundp( xform( aEndPoint ) );
 const VECTOR2D p3 = roundp( xform( VECTOR2D( aStartPoint.x, aEndPoint.y ) ) );

 // The path is composed from 4 segments
 cairo_move_to( m_currentContext, p0.x, p0.y );
 cairo_line_to( m_currentContext, p1.x, p1.y );
 cairo_line_to( m_currentContext, p2.x, p2.y );
 cairo_line_to( m_currentContext, p3.x, p3.y );
 cairo_close_path( m_currentContext );
 flushPath();

 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::DrawPolygon( const SHAPE_POLY_SET& aPolySet, bool aStrokeTriangulation )
{
 for( int i = 0; i < aPolySet.OutlineCount(); ++i )
 drawPoly( aPolySet.COutline( i ) );
}


void CAIRO_GAL_BASE::DrawPolygon( const SHAPE_LINE_CHAIN& aPolygon )
{
 drawPoly( aPolygon );
}


void CAIRO_GAL_BASE::DrawCurve( const VECTOR2D& aStartPoint, const VECTOR2D& aControlPointA,
 const VECTOR2D& aControlPointB, const VECTOR2D& aEndPoint,
 double aFilterValue )
{
 // Note: aFilterValue is not used because the cubic Bezier curve is
 // supported by Cairo.
 syncLineWidth();

 const VECTOR2D sp = roundp( xform( aStartPoint ) );
 const VECTOR2D cpa = roundp( xform( aControlPointA ) );
 const VECTOR2D cpb = roundp( xform( aControlPointB ) );
 const VECTOR2D ep = roundp( xform( aEndPoint ) );

 cairo_move_to( m_currentContext, sp.x, sp.y );
 cairo_curve_to( m_currentContext, cpa.x, cpa.y, cpb.x, cpb.y, ep.x, ep.y );
 cairo_line_to( m_currentContext, ep.x, ep.y );

 flushPath();
 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::DrawBitmap( const BITMAP_BASE& aBitmap )
{
 cairo_save( m_currentContext );

 // We have to calculate the pixel size in users units to draw the image.
 // m_worldUnitLength is a factor used for converting IU to inches
 double scale = 1.0 / ( aBitmap.GetPPI() * m_worldUnitLength );

 // The position of the bitmap is the bitmap center.
 // move the draw origin to the top left bitmap corner:
 int w = aBitmap.GetSizePixels().x;
 int h = aBitmap.GetSizePixels().y;

 cairo_set_matrix( m_currentContext, &m_currentWorld2Screen );
 cairo_scale( m_currentContext, scale, scale );
 cairo_translate( m_currentContext, -w / 2.0, -h / 2.0 );

 cairo_new_path( m_currentContext );
 cairo_surface_t* image = cairo_image_surface_create( CAIRO_FORMAT_ARGB32, w, h );
 cairo_surface_flush( image );

 unsigned char* pix_buffer = cairo_image_surface_get_data( image );

 // The pixel buffer of the initial bitmap:
 const wxImage& bm_pix_buffer = *aBitmap.GetImageData();

 uint32_t mask_color = ( bm_pix_buffer.GetMaskRed() << 16 )
 + ( bm_pix_buffer.GetMaskGreen() << 8 ) + ( bm_pix_buffer.GetMaskBlue() );

 // Copy the source bitmap to the cairo bitmap buffer.
 // In cairo bitmap buffer, a ARGB32 bitmap is an ARGB pixel packed into a uint_32
 // 24 low bits only are used for color, top 8 are transparency.
 for( int row = 0; row < h; row++ )
 {
 for( int col = 0; col < w; col++ )
 {
 // Build the RGB24 pixel:
 uint32_t pixel = bm_pix_buffer.GetRed( col, row ) << 16;
 pixel += bm_pix_buffer.GetGreen( col, row ) << 8;
 pixel += bm_pix_buffer.GetBlue( col, row );

 if( bm_pix_buffer.HasAlpha() )
 pixel += bm_pix_buffer.GetAlpha( col, row ) << 24;
 else if( bm_pix_buffer.HasMask() && pixel == mask_color )
 pixel += ( wxALPHA_TRANSPARENT << 24 );
 else
 pixel += ( wxALPHA_OPAQUE << 24 );

 // Write the pixel to the cairo image buffer:
 uint32_t* pix_ptr = (uint32_t*) pix_buffer;
 *pix_ptr = pixel;
 pix_buffer += 4;
 }
 }

 cairo_surface_mark_dirty( image );
 cairo_set_source_surface( m_currentContext, image, 0, 0 );
 cairo_paint( m_currentContext );

 // store the image handle so it can be destroyed later
 m_imageSurfaces.push_back( image );

 m_isElementAdded = true;

 cairo_restore( m_currentContext );
}


void CAIRO_GAL_BASE::ResizeScreen( int aWidth, int aHeight )
{
 m_screenSize = VECTOR2I( aWidth, aHeight );
}


void CAIRO_GAL_BASE::Flush()
{
 storePath();
}


void CAIRO_GAL_BASE::ClearScreen()
{
 cairo_set_source_rgb( m_currentContext, m_clearColor.r, m_clearColor.g, m_clearColor.b );
 cairo_rectangle( m_currentContext, 0.0, 0.0, m_screenSize.x, m_screenSize.y );
 cairo_fill( m_currentContext );
}


void CAIRO_GAL_BASE::SetIsFill( bool aIsFillEnabled )
{
 storePath();
 m_isFillEnabled = aIsFillEnabled;

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_SET_FILL;
 groupElement.m_Argument.BoolArg = aIsFillEnabled;
 m_currentGroup->push_back( groupElement );
 }
}


void CAIRO_GAL_BASE::SetIsStroke( bool aIsStrokeEnabled )
{
 storePath();
 m_isStrokeEnabled = aIsStrokeEnabled;

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_SET_STROKE;
 groupElement.m_Argument.BoolArg = aIsStrokeEnabled;
 m_currentGroup->push_back( groupElement );
 }
}


void CAIRO_GAL_BASE::SetStrokeColor( const COLOR4D& aColor )
{
 storePath();
 m_strokeColor = aColor;

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_SET_STROKECOLOR;
 groupElement.m_Argument.DblArg[0] = m_strokeColor.r;
 groupElement.m_Argument.DblArg[1] = m_strokeColor.g;
 groupElement.m_Argument.DblArg[2] = m_strokeColor.b;
 groupElement.m_Argument.DblArg[3] = m_strokeColor.a;
 m_currentGroup->push_back( groupElement );
 }
}


void CAIRO_GAL_BASE::SetFillColor( const COLOR4D& aColor )
{
 storePath();
 m_fillColor = aColor;

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_SET_FILLCOLOR;
 groupElement.m_Argument.DblArg[0] = m_fillColor.r;
 groupElement.m_Argument.DblArg[1] = m_fillColor.g;
 groupElement.m_Argument.DblArg[2] = m_fillColor.b;
 groupElement.m_Argument.DblArg[3] = m_fillColor.a;
 m_currentGroup->push_back( groupElement );
 }
}


void CAIRO_GAL_BASE::SetLineWidth( float aLineWidth )
{
 storePath();
 GAL::SetLineWidth( aLineWidth );

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_SET_LINE_WIDTH;
 groupElement.m_Argument.DblArg[0] = aLineWidth;
 m_currentGroup->push_back( groupElement );
 }
 else
 {
 m_lineWidth = aLineWidth;
 }
}


void CAIRO_GAL_BASE::SetLayerDepth( double aLayerDepth )
{
 super::SetLayerDepth( aLayerDepth );
 storePath();
}


void CAIRO_GAL_BASE::Transform( const MATRIX3x3D& aTransformation )
{
 cairo_matrix_t cairoTransformation, newXform;

 cairo_matrix_init( &cairoTransformation, aTransformation.m_data[0][0],
 aTransformation.m_data[1][0], aTransformation.m_data[0][1],
 aTransformation.m_data[1][1], aTransformation.m_data[0][2],
 aTransformation.m_data[1][2] );

 cairo_matrix_multiply( &newXform, &m_currentXform, &cairoTransformation );
 m_currentXform = newXform;
 updateWorldScreenMatrix();
}


void CAIRO_GAL_BASE::Rotate( double aAngle )
{
 storePath();

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_ROTATE;
 groupElement.m_Argument.DblArg[0] = aAngle;
 m_currentGroup->push_back( groupElement );
 }
 else
 {
 cairo_matrix_rotate( &m_currentXform, aAngle );
 updateWorldScreenMatrix();
 }
}


void CAIRO_GAL_BASE::Translate( const VECTOR2D& aTranslation )
{
 storePath();

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_TRANSLATE;
 groupElement.m_Argument.DblArg[0] = aTranslation.x;
 groupElement.m_Argument.DblArg[1] = aTranslation.y;
 m_currentGroup->push_back( groupElement );
 }
 else
 {
 cairo_matrix_translate( &m_currentXform, aTranslation.x, aTranslation.y );
 updateWorldScreenMatrix();
 }
}


void CAIRO_GAL_BASE::Scale( const VECTOR2D& aScale )
{
 storePath();

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_SCALE;
 groupElement.m_Argument.DblArg[0] = aScale.x;
 groupElement.m_Argument.DblArg[1] = aScale.y;
 m_currentGroup->push_back( groupElement );
 }
 else
 {
 cairo_matrix_scale( &m_currentXform, aScale.x, aScale.y );
 updateWorldScreenMatrix();
 }
}


void CAIRO_GAL_BASE::Save()
{
 storePath();

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_SAVE;
 m_currentGroup->push_back( groupElement );
 }
 else
 {
 m_xformStack.push_back( m_currentXform );
 updateWorldScreenMatrix();
 }
}


void CAIRO_GAL_BASE::Restore()
{
 storePath();

 if( m_isGrouping )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_Command = CMD_RESTORE;
 m_currentGroup->push_back( groupElement );
 }
 else
 {
 if( !m_xformStack.empty() )
 {
 m_currentXform = m_xformStack.back();
 m_xformStack.pop_back();
 updateWorldScreenMatrix();
 }
 }
}


int CAIRO_GAL_BASE::BeginGroup()
{
 // If the grouping is started: the actual path is stored in the group, when
 // a attribute was changed or when grouping stops with the end group method.
 storePath();

 GROUP group;
 int groupNumber = getNewGroupNumber();
 m_groups.insert( std::make_pair( groupNumber, group ) );
 m_currentGroup = &m_groups[groupNumber];
 m_isGrouping = true;

 return groupNumber;
}


void CAIRO_GAL_BASE::EndGroup()
{
 storePath();
 m_isGrouping = false;
}


void CAIRO_GAL_BASE::DrawGroup( int aGroupNumber )
{
 // This method implements a small Virtual Machine - all stored commands
 // are executed; nested calling is also possible

 storePath();

 for( auto it = m_groups[aGroupNumber].begin(); it != m_groups[aGroupNumber].end(); ++it )
 {
 switch( it->m_Command )
 {
 case CMD_SET_FILL:
 m_isFillEnabled = it->m_Argument.BoolArg;
 break;

 case CMD_SET_STROKE:
 m_isStrokeEnabled = it->m_Argument.BoolArg;
 break;

 case CMD_SET_FILLCOLOR:
 m_fillColor = COLOR4D( it->m_Argument.DblArg[0], it->m_Argument.DblArg[1],
 it->m_Argument.DblArg[2], it->m_Argument.DblArg[3] );
 break;

 case CMD_SET_STROKECOLOR:
 m_strokeColor = COLOR4D( it->m_Argument.DblArg[0], it->m_Argument.DblArg[1],
 it->m_Argument.DblArg[2], it->m_Argument.DblArg[3] );
 break;

 case CMD_SET_LINE_WIDTH:
 {
 // Make lines appear at least 1 pixel wide, no matter of zoom
 double x = 1.0, y = 1.0;
 cairo_device_to_user_distance( m_currentContext, &x, &y );
 double minWidth = std::min( fabs( x ), fabs( y ) );
 cairo_set_line_width( m_currentContext,
 std::max( it->m_Argument.DblArg[0], minWidth ) );
 break;
 }


 case CMD_STROKE_PATH:
 cairo_set_source_rgba( m_currentContext, m_strokeColor.r, m_strokeColor.g,
 m_strokeColor.b, m_strokeColor.a );
 cairo_append_path( m_currentContext, it->m_CairoPath );
 cairo_stroke( m_currentContext );
 break;

 case CMD_FILL_PATH:
 cairo_set_source_rgba( m_currentContext, m_fillColor.r, m_fillColor.g, m_fillColor.b,
 m_strokeColor.a );
 cairo_append_path( m_currentContext, it->m_CairoPath );
 cairo_fill( m_currentContext );
  break;

 /*
 case CMD_TRANSFORM:
 cairo_matrix_t matrix;
 cairo_matrix_init( &matrix, it->argument.DblArg[0], it->argument.DblArg[1],
 it->argument.DblArg[2], it->argument.DblArg[3],
 it->argument.DblArg[4], it->argument.DblArg[5] );
 cairo_transform( m_currentContext, &matrix );
 break;
 */

 case CMD_ROTATE:
 cairo_rotate( m_currentContext, it->m_Argument.DblArg[0] );
 break;

 case CMD_TRANSLATE:
 cairo_translate( m_currentContext, it->m_Argument.DblArg[0], it->m_Argument.DblArg[1] );
 break;

 case CMD_SCALE:
 cairo_scale( m_currentContext, it->m_Argument.DblArg[0], it->m_Argument.DblArg[1] );
 break;

 case CMD_SAVE:
 cairo_save( m_currentContext );
 break;

 case CMD_RESTORE:
 cairo_restore( m_currentContext );
 break;

 case CMD_CALL_GROUP:
 DrawGroup( it->m_Argument.IntArg );
 break;
 }
 }
}


void CAIRO_GAL_BASE::ChangeGroupColor( int aGroupNumber, const COLOR4D& aNewColor )
{
 storePath();

 for( auto it = m_groups[aGroupNumber].begin(); it != m_groups[aGroupNumber].end(); ++it )
 {
 if( it->m_Command == CMD_SET_FILLCOLOR || it->m_Command == CMD_SET_STROKECOLOR )
 {
 it->m_Argument.DblArg[0] = aNewColor.r;
 it->m_Argument.DblArg[1] = aNewColor.g;
 it->m_Argument.DblArg[2] = aNewColor.b;
 it->m_Argument.DblArg[3] = aNewColor.a;
 }
 }
}


void CAIRO_GAL_BASE::ChangeGroupDepth( int aGroupNumber, int aDepth )
{
 // Cairo does not have any possibilities to change the depth coordinate of stored items,
 // it depends only on the order of drawing
}


void CAIRO_GAL_BASE::DeleteGroup( int aGroupNumber )
{
 storePath();

 // Delete the Cairo paths
 std::deque<GROUP_ELEMENT>::iterator it, end;

 for( it = m_groups[aGroupNumber].begin(), end = m_groups[aGroupNumber].end(); it != end; ++it )
 {
 if( it->m_Command == CMD_FILL_PATH || it->m_Command == CMD_STROKE_PATH )
 cairo_path_destroy( it->m_CairoPath );
 }

 // Delete the group
 m_groups.erase( aGroupNumber );
}


void CAIRO_GAL_BASE::ClearCache()
{
 for( auto it = m_groups.begin(); it != m_groups.end(); )
 DeleteGroup( ( it++ )->first );
}


void CAIRO_GAL_BASE::SetNegativeDrawMode( bool aSetting )
{
 cairo_set_operator( m_currentContext, aSetting ? CAIRO_OPERATOR_CLEAR : CAIRO_OPERATOR_OVER );
}


void CAIRO_GAL::StartDiffLayer()
{
 SetTarget( TARGET_TEMP );
 ClearTarget( TARGET_TEMP );
}


void CAIRO_GAL::EndDiffLayer()
{
 m_compositor->DrawBuffer( m_tempBuffer, m_mainBuffer, CAIRO_OPERATOR_ADD );
}


void CAIRO_GAL::StartNegativesLayer()
{
 SetTarget( TARGET_TEMP );
 ClearTarget( TARGET_TEMP );
}


void CAIRO_GAL::EndNegativesLayer()
{
 m_compositor->DrawBuffer( m_tempBuffer, m_mainBuffer, CAIRO_OPERATOR_OVER );
}


void CAIRO_GAL_BASE::DrawCursor( const VECTOR2D& aCursorPosition )
{
 m_cursorPosition = aCursorPosition;
}


void CAIRO_GAL_BASE::EnableDepthTest( bool aEnabled )
{
}


void CAIRO_GAL_BASE::resetContext()
{
 for( _cairo_surface* imageSurface : m_imageSurfaces )
 cairo_surface_destroy( imageSurface );

 m_imageSurfaces.clear();

 ClearScreen();

 // Compute the world <-> screen transformations
 ComputeWorldScreenMatrix();

 cairo_matrix_init( &m_cairoWorldScreenMatrix, m_worldScreenMatrix.m_data[0][0],
 m_worldScreenMatrix.m_data[1][0], m_worldScreenMatrix.m_data[0][1],
 m_worldScreenMatrix.m_data[1][1], m_worldScreenMatrix.m_data[0][2],
 m_worldScreenMatrix.m_data[1][2] );

 // we work in screen-space coordinates and do the transforms outside.
 cairo_identity_matrix( m_context );

 cairo_matrix_init_identity( &m_currentXform );

 // Start drawing with a new path
 cairo_new_path( m_context );
 m_isElementAdded = true;

 updateWorldScreenMatrix();

 m_lineWidth = 0;
}


void CAIRO_GAL_BASE::drawAxes( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint )
{
 syncLineWidth();

 VECTOR2D p0 = roundp( xform( aStartPoint ) );
 VECTOR2D p1 = roundp( xform( aEndPoint ) );
 VECTOR2D org = roundp( xform( VECTOR2D( 0.0, 0.0 ) ) ); // Axis origin = 0,0 coord

 cairo_set_source_rgba( m_currentContext, m_axesColor.r, m_axesColor.g, m_axesColor.b,
 m_axesColor.a );
 cairo_move_to( m_currentContext, p0.x, org.y );
 cairo_line_to( m_currentContext, p1.x, org.y );
 cairo_move_to( m_currentContext, org.x, p0.y );
 cairo_line_to( m_currentContext, org.x, p1.y );
 cairo_stroke( m_currentContext );
}


void CAIRO_GAL_BASE::drawGridLine( const VECTOR2D& aStartPoint, const VECTOR2D& aEndPoint )
{
 syncLineWidth();
 VECTOR2D p0 = roundp( xform( aStartPoint ) );
 VECTOR2D p1 = roundp( xform( aEndPoint ) );

 cairo_set_source_rgba( m_currentContext, m_gridColor.r, m_gridColor.g, m_gridColor.b,
 m_gridColor.a );
 cairo_move_to( m_currentContext, p0.x, p0.y );
 cairo_line_to( m_currentContext, p1.x, p1.y );
 cairo_stroke( m_currentContext );
}


void CAIRO_GAL_BASE::drawGridCross( const VECTOR2D& aPoint )
{
 syncLineWidth();
 VECTOR2D offset( 0, 0 );
 double size = 2.0 * m_lineWidthInPixels + 0.5;

 VECTOR2D p0 = roundp( xform( aPoint ) ) - VECTOR2D( size, 0 ) + offset;
 VECTOR2D p1 = roundp( xform( aPoint ) ) + VECTOR2D( size, 0 ) + offset;
 VECTOR2D p2 = roundp( xform( aPoint ) ) - VECTOR2D( 0, size ) + offset;
 VECTOR2D p3 = roundp( xform( aPoint ) ) + VECTOR2D( 0, size ) + offset;

 cairo_set_source_rgba( m_currentContext, m_gridColor.r, m_gridColor.g, m_gridColor.b,
 m_gridColor.a );
 cairo_move_to( m_currentContext, p0.x, p0.y );
 cairo_line_to( m_currentContext, p1.x, p1.y );
 cairo_move_to( m_currentContext, p2.x, p2.y );
 cairo_line_to( m_currentContext, p3.x, p3.y );
 cairo_stroke( m_currentContext );
}


void CAIRO_GAL_BASE::drawGridPoint( const VECTOR2D& aPoint, double aWidth, double aHeight )
{
 VECTOR2D p = roundp( xform( aPoint ) );

 double sw = std::max( 1.0, aWidth );
 double sh = std::max( 1.0, aHeight );

 cairo_set_source_rgba( m_currentContext, m_gridColor.r, m_gridColor.g, m_gridColor.b,
 m_gridColor.a );
 cairo_rectangle( m_currentContext, p.x - std::floor( sw / 2 ) - 0.5,
 p.y - std::floor( sh / 2 ) - 0.5, sw, sh );

 cairo_fill( m_currentContext );
}


void CAIRO_GAL_BASE::flushPath()
{
 if( m_isFillEnabled )
 {
 cairo_set_source_rgba( m_currentContext, m_fillColor.r, m_fillColor.g, m_fillColor.b,
 m_fillColor.a );

 if( m_isStrokeEnabled )
 {
 cairo_set_line_width( m_currentContext, m_lineWidthInPixels );
 cairo_fill_preserve( m_currentContext );
 }
 else
 {
 cairo_fill( m_currentContext );
 }
 }

 if( m_isStrokeEnabled )
 {
 cairo_set_line_width( m_currentContext, m_lineWidthInPixels );
 cairo_set_source_rgba( m_currentContext, m_strokeColor.r, m_strokeColor.g, m_strokeColor.b,
 m_strokeColor.a );
 cairo_stroke( m_currentContext );
 }
}


void CAIRO_GAL_BASE::storePath()
{
 if( m_isElementAdded )
 {
 m_isElementAdded = false;

 if( !m_isGrouping )
 {
 if( m_isFillEnabled )
 {
 cairo_set_source_rgba( m_currentContext, m_fillColor.r, m_fillColor.g,
 m_fillColor.b, m_fillColor.a );
 cairo_fill_preserve( m_currentContext );
 }

 if( m_isStrokeEnabled )
 {
 cairo_set_source_rgba( m_currentContext, m_strokeColor.r, m_strokeColor.g,
 m_strokeColor.b, m_strokeColor.a );
 cairo_stroke_preserve( m_currentContext );
 }
 }
 else
 {
 // Copy the actual path, append it to the global path list
 // then check, if the path needs to be stroked/filled and
 // add this command to the group list;
 if( m_isStrokeEnabled )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_CairoPath = cairo_copy_path( m_currentContext );
 groupElement.m_Command = CMD_STROKE_PATH;
 m_currentGroup->push_back( groupElement );
 }

 if( m_isFillEnabled )
 {
 GROUP_ELEMENT groupElement;
 groupElement.m_CairoPath = cairo_copy_path( m_currentContext );
 groupElement.m_Command = CMD_FILL_PATH;
 m_currentGroup->push_back( groupElement );
 }
 }

 cairo_new_path( m_currentContext );
 }
}


void CAIRO_GAL_BASE::blitCursor( wxMemoryDC& clientDC )
{
 if( !IsCursorEnabled() )
 return;

 VECTOR2D p = ToScreen( m_cursorPosition );
 const COLOR4D cColor = getCursorColor();
 const int cursorSize = m_fullscreenCursor ? 8000 : 80;

 wxColour color( cColor.r * cColor.a * 255, cColor.g * cColor.a * 255, cColor.b * cColor.a * 255,
 255 );
 clientDC.SetPen( wxPen( color ) );
 clientDC.DrawLine( p.x - cursorSize / 2, p.y, p.x + cursorSize / 2, p.y );
 clientDC.DrawLine( p.x, p.y - cursorSize / 2, p.x, p.y + cursorSize / 2 );
}


void CAIRO_GAL_BASE::drawPoly( const std::deque<VECTOR2D>& aPointList )
{
 wxCHECK( aPointList.size() > 1, /* void */ );

 // Iterate over the point list and draw the segments
 std::deque<VECTOR2D>::const_iterator it = aPointList.begin();

 syncLineWidth();

 const VECTOR2D p = roundp( xform( it->x, it->y ) );

 cairo_move_to( m_currentContext, p.x, p.y );

 for( ++it; it != aPointList.end(); ++it )
 {
 const VECTOR2D p2 = roundp( xform( it->x, it->y ) );

 cairo_line_to( m_currentContext, p2.x, p2.y );
 }

 flushPath();
 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::drawPoly( const VECTOR2D aPointList[], int aListSize )
{
 wxCHECK( aListSize > 1, /* void */ );

 // Iterate over the point list and draw the segments
 const VECTOR2D* ptr = aPointList;

 syncLineWidth();

 const VECTOR2D p = roundp( xform( ptr->x, ptr->y ) );
 cairo_move_to( m_currentContext, p.x, p.y );

 for( int i = 1; i < aListSize; ++i )
 {
 ++ptr;
 const VECTOR2D p2 = roundp( xform( ptr->x, ptr->y ) );
 cairo_line_to( m_currentContext, p2.x, p2.y );
 }

 flushPath();
 m_isElementAdded = true;
}


void CAIRO_GAL_BASE::drawPoly( const SHAPE_LINE_CHAIN& aLineChain )
{
 wxCHECK( aLineChain.PointCount() > 1, /* void */ );

 syncLineWidth();

 auto numPoints = aLineChain.PointCount();

 if( aLineChain.IsClosed() )
 numPoints += 1;

 const VECTOR2I start = aLineChain.CPoint( 0 );
 const VECTOR2D p = roundp( xform( start.x, start.y ) );
 cairo_move_to( m_currentContext, p.x, p.y );

 for( int i = 1; i < numPoints; ++i )
 {
 const VECTOR2I& pw = aLineChain.CPoint( i );
 const VECTOR2D ps = roundp( xform( pw.x, pw.y ) );
 cairo_line_to( m_currentContext, ps.x, ps.y );
 }

 flushPath();
 m_isElementAdded = true;
}


unsigned int CAIRO_GAL_BASE::getNewGroupNumber()
{
 wxASSERT_MSG( m_groups.size() < std::numeric_limits<unsigned int>::max(),
 wxT( "There are no free slots to store a group" ) );

 while( m_groups.find( m_groupCounter ) != m_groups.end() )
 m_groupCounter++;

 return m_groupCounter++;
}


CAIRO_GAL::CAIRO_GAL( GAL_DISPLAY_OPTIONS& aDisplayOptions, wxWindow* aParent,
 wxEvtHandler* aMouseListener, wxEvtHandler* aPaintListener,
 const wxString& aName ) :
 CAIRO_GAL_BASE( aDisplayOptions ),
 wxWindow( aParent, wxID_ANY, wxDefaultPosition, wxDefaultSize, wxEXPAND, aName )
{
 // Initialise compositing state
 m_mainBuffer = 0;
 m_overlayBuffer = 0;
 m_tempBuffer = 0;
 m_savedBuffer = 0;
 m_validCompositor = false;
 SetTarget( TARGET_NONCACHED );

 m_bitmapBuffer = nullptr;
 m_wxOutput = nullptr;

 m_parentWindow = aParent;
 m_mouseListener = aMouseListener;
 m_paintListener = aPaintListener;

 // Connect the native cursor handler
 Connect( wxEVT_SET_CURSOR, wxSetCursorEventHandler( CAIRO_GAL::onSetNativeCursor ), nullptr,
 this );

 // Connecting the event handlers
 Connect( wxEVT_PAINT, wxPaintEventHandler( CAIRO_GAL::onPaint ) );

 // Mouse events are skipped to the parent
 Connect( wxEVT_MOTION, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_LEFT_DOWN, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_LEFT_UP, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_LEFT_DCLICK, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_MIDDLE_DOWN, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_MIDDLE_UP, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_MIDDLE_DCLICK, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_RIGHT_DOWN, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_RIGHT_UP, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_RIGHT_DCLICK, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
 Connect( wxEVT_MOUSEWHEEL, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
#if defined _WIN32 || defined _WIN64
 Connect( wxEVT_ENTER_WINDOW, wxMouseEventHandler( CAIRO_GAL::skipMouseEvent ) );
#endif

 SetSize( aParent->GetClientSize() );
 m_screenSize = VECTOR2I( aParent->GetClientSize() );

 // Allocate memory for pixel storage
 allocateBitmaps();

 m_isInitialized = false;
}


CAIRO_GAL::~CAIRO_GAL()
{
 deleteBitmaps();
}


void CAIRO_GAL::BeginDrawing()
{
 initSurface();

 CAIRO_GAL_BASE::BeginDrawing();

 if( !m_validCompositor )
 setCompositor();

 m_compositor->SetMainContext( m_context );
 m_compositor->SetBuffer( m_mainBuffer );
}


void CAIRO_GAL::EndDrawing()
{
 CAIRO_GAL_BASE::EndDrawing();

 // Merge buffers on the screen
 m_compositor->DrawBuffer( m_mainBuffer );
 m_compositor->DrawBuffer( m_overlayBuffer );

 // Now translate the raw context data from the format stored
 // by cairo into a format understood by wxImage.
 pixman_image_t* dstImg = pixman_image_create_bits(
 wxPlatformInfo::Get().GetEndianness() == wxENDIAN_LITTLE ? PIXMAN_b8g8r8
 : PIXMAN_r8g8b8,
 m_screenSize.x, m_screenSize.y, (uint32_t*) m_wxOutput, m_wxBufferWidth * 3 );
 pixman_image_t* srcImg =
 pixman_image_create_bits( PIXMAN_a8r8g8b8, m_screenSize.x, m_screenSize.y,
 (uint32_t*) m_bitmapBuffer, m_wxBufferWidth * 4 );

 pixman_image_composite( PIXMAN_OP_SRC, srcImg, nullptr, dstImg, 0, 0, 0, 0, 0, 0,
 m_screenSize.x, m_screenSize.y );

 // Free allocated memory
 pixman_image_unref( srcImg );
 pixman_image_unref( dstImg );

 wxImage img( m_wxBufferWidth, m_screenSize.y, m_wxOutput, true );
 wxBitmap bmp( img );
 wxMemoryDC mdc( bmp );
 wxClientDC clientDC( this );

 // Now it is the time to blit the mouse cursor
 blitCursor( mdc );
 clientDC.Blit( 0, 0, m_screenSize.x, m_screenSize.y, &mdc, 0, 0, wxCOPY );

 deinitSurface();
}


void CAIRO_GAL::PostPaint( wxPaintEvent& aEvent )
{
 // posts an event to m_paint_listener to ask for redraw the canvas.
 if( m_paintListener )
 wxPostEvent( m_paintListener, aEvent );
}


void CAIRO_GAL::ResizeScreen( int aWidth, int aHeight )
{
 CAIRO_GAL_BASE::ResizeScreen( aWidth, aHeight );

 // Recreate the bitmaps
 deleteBitmaps();
 allocateBitmaps();

 if( m_validCompositor )
 m_compositor->Resize( aWidth, aHeight );

 m_validCompositor = false;

 SetSize( wxSize( aWidth, aHeight ) );
}


bool CAIRO_GAL::Show( bool aShow )
{
 bool s = wxWindow::Show( aShow );

 if( aShow )
 wxWindow::Raise();

 return s;
}


int CAIRO_GAL::BeginGroup()
{
 initSurface();
 return CAIRO_GAL_BASE::BeginGroup();
}


void CAIRO_GAL::EndGroup()
{
 CAIRO_GAL_BASE::EndGroup();
 deinitSurface();
}


void CAIRO_GAL::SetTarget( RENDER_TARGET aTarget )
{
 // If the compositor is not set, that means that there is a recaching process going on
 // and we do not need the compositor now
 if( !m_validCompositor )
 return;

 // Cairo grouping prevents display of overlapping items on the same layer in the lighter color
 if( m_isInitialized )
 storePath();

 switch( aTarget )
 {
 default:
 case TARGET_CACHED:
 case TARGET_NONCACHED: m_compositor->SetBuffer( m_mainBuffer ); break;
 case TARGET_OVERLAY: m_compositor->SetBuffer( m_overlayBuffer ); break;
 case TARGET_TEMP: m_compositor->SetBuffer( m_tempBuffer ); break;
 }

 m_currentTarget = aTarget;
}


RENDER_TARGET CAIRO_GAL::GetTarget() const
{
 return m_currentTarget;
}


void CAIRO_GAL::ClearTarget( RENDER_TARGET aTarget )
{
 // Save the current state
 unsigned int currentBuffer = m_compositor->GetBuffer();

 switch( aTarget )
 {
 // Cached and noncached items are rendered to the same buffer
 default:
 case TARGET_CACHED:
 case TARGET_NONCACHED: m_compositor->SetBuffer( m_mainBuffer ); break;
 case TARGET_OVERLAY: m_compositor->SetBuffer( m_overlayBuffer ); break;
 case TARGET_TEMP: m_compositor->SetBuffer( m_tempBuffer ); break;
 }

 m_compositor->ClearBuffer( COLOR4D::BLACK );

 // Restore the previous state
 m_compositor->SetBuffer( currentBuffer );
}


void CAIRO_GAL::initSurface()
{
 if( m_isInitialized )
 return;

 m_surface = cairo_image_surface_create_for_data( m_bitmapBuffer, GAL_FORMAT, m_wxBufferWidth,
 m_screenSize.y, m_stride );

 m_context = cairo_create( m_surface );

#ifdef DEBUG
 cairo_status_t status = cairo_status( m_context );
 wxASSERT_MSG( status == CAIRO_STATUS_SUCCESS, wxT( "Cairo context creation error" ) );
#endif /* DEBUG */

 m_currentContext = m_context;

 m_isInitialized = true;
}


void CAIRO_GAL::deinitSurface()
{
 if( !m_isInitialized )
 return;

 cairo_destroy( m_context );
 m_context = nullptr;
 cairo_surface_destroy( m_surface );
 m_surface = nullptr;

 m_isInitialized = false;
}


void CAIRO_GAL::allocateBitmaps()
{
 m_wxBufferWidth = m_screenSize.x;

 while( ( ( m_wxBufferWidth * 3 ) % 4 ) != 0 )
 m_wxBufferWidth++;

 // Create buffer, use the system independent Cairo context backend
 m_stride = cairo_format_stride_for_width( GAL_FORMAT, m_wxBufferWidth );
 m_bufferSize = m_stride * m_screenSize.y;

 wxASSERT( m_bitmapBuffer == nullptr );
 m_bitmapBuffer = new unsigned char[m_bufferSize * 4];

 wxASSERT( m_wxOutput == nullptr );
 m_wxOutput = new unsigned char[m_wxBufferWidth * 3 * m_screenSize.y];
}


void CAIRO_GAL::deleteBitmaps()
{
 delete[] m_bitmapBuffer;
 m_bitmapBuffer = nullptr;

 delete[] m_wxOutput;
 m_wxOutput = nullptr;
}


void CAIRO_GAL::setCompositor()
{
 // Recreate the compositor with the new Cairo context
 m_compositor.reset( new CAIRO_COMPOSITOR( &m_currentContext ) );
 m_compositor->Resize( m_screenSize.x, m_screenSize.y );
 m_compositor->SetAntialiasingMode( m_options.cairo_antialiasing_mode );

 // Prepare buffers
 m_mainBuffer = m_compositor->CreateBuffer();
 m_overlayBuffer = m_compositor->CreateBuffer();
 m_tempBuffer = m_compositor->CreateBuffer();

 m_validCompositor = true;
}


void CAIRO_GAL::onPaint( wxPaintEvent& aEvent )
{
 PostPaint( aEvent );
}


void CAIRO_GAL::skipMouseEvent( wxMouseEvent& aEvent )
{
 // Post the mouse event to the event listener registered in constructor, if any
 if( m_mouseListener )
 wxPostEvent( m_mouseListener, aEvent );
}


bool CAIRO_GAL::updatedGalDisplayOptions( const GAL_DISPLAY_OPTIONS& aOptions )
{
 bool refresh = false;

 if( m_validCompositor &&
 aOptions.cairo_antialiasing_mode != m_compositor->GetAntialiasingMode() )
 {
  m_compositor->SetAntialiasingMode( m_options.cairo_antialiasing_mode );
 m_validCompositor = false;
 deinitSurface();

 refresh = true;
 }

 if( super::updatedGalDisplayOptions( aOptions ) )
 {
 Refresh();
 refresh = true;
 }

 return refresh;
}


bool CAIRO_GAL::SetNativeCursorStyle( KICURSOR aCursor )
{
 // Store the current cursor type and get the wxCursor for it
 if( !GAL::SetNativeCursorStyle( aCursor ) )
 return false;

 m_currentwxCursor = CURSOR_STORE::GetCursor( m_currentNativeCursor );

 // Update the cursor in the wx control
 wxWindow::SetCursor( m_currentwxCursor );

 return true;
}


void CAIRO_GAL::onSetNativeCursor( wxSetCursorEvent& aEvent )
{
 aEvent.SetCursor( m_currentwxCursor );
}


void CAIRO_GAL_BASE::DrawGrid()
{
 SetTarget( TARGET_NONCACHED );

 // Draw the grid
 // For the drawing the start points, end points and increments have
 // to be calculated in world coordinates
 VECTOR2D worldStartPoint = m_screenWorldMatrix * VECTOR2D( 0.0, 0.0 );
 VECTOR2D worldEndPoint = m_screenWorldMatrix * VECTOR2D( m_screenSize );

 // Compute the line marker or point radius of the grid
 // Note: generic grids can't handle sub-pixel lines without
 // either losing fine/course distinction or having some dots
 // fail to render
 float marker = std::fmax( 1.0f, m_gridLineWidth ) / m_worldScale;
 float doubleMarker = 2.0f * marker;

 // Draw axes if desired
 if( m_axesEnabled )
 {
 SetLineWidth( marker );
 drawAxes( worldStartPoint, worldEndPoint );
 }

 if( !m_gridVisibility || m_gridSize.x == 0 || m_gridSize.y == 0 )
 return;

 VECTOR2D gridScreenSize( m_gridSize );

 double gridThreshold = KiROUND( computeMinGridSpacing() / m_worldScale );

 if( m_gridStyle == GRID_STYLE::SMALL_CROSS )
 gridThreshold *= 2.0;

 // If we cannot display the grid density, scale down by a tick size and
 // try again. Eventually, we get some representation of the grid
 while( std::min( gridScreenSize.x, gridScreenSize.y ) <= gridThreshold )
 {
 gridScreenSize = gridScreenSize * static_cast<double>( m_gridTick );
 }

 // Compute grid starting and ending indexes to draw grid points on the
 // visible screen area
 // Note: later any point coordinate will be offsetted by m_gridOrigin
 int gridStartX = KiROUND( ( worldStartPoint.x - m_gridOrigin.x ) / gridScreenSize.x );
 int gridEndX = KiROUND( ( worldEndPoint.x - m_gridOrigin.x ) / gridScreenSize.x );
 int gridStartY = KiROUND( ( worldStartPoint.y - m_gridOrigin.y ) / gridScreenSize.y );
 int gridEndY = KiROUND( ( worldEndPoint.y - m_gridOrigin.y ) / gridScreenSize.y );

 // Ensure start coordinate > end coordinate
 SWAP( gridStartX, >, gridEndX );
 SWAP( gridStartY, >, gridEndY );

 // Ensure the grid fills the screen
 --gridStartX;
 ++gridEndX;
 --gridStartY;
 ++gridEndY;

 // Draw the grid behind all other layers
 SetLayerDepth( m_depthRange.y * 0.75 );

 if( m_gridStyle == GRID_STYLE::LINES )
 {
 // Now draw the grid, every coarse grid line gets the double width

 // Vertical lines
 for( int j = gridStartY; j <= gridEndY; j++ )
 {
 const double y = j * gridScreenSize.y + m_gridOrigin.y;

 if( m_axesEnabled && y == 0.0 )
 continue;

 SetLineWidth( ( j % m_gridTick ) ? marker : doubleMarker );
 drawGridLine( VECTOR2D( gridStartX * gridScreenSize.x + m_gridOrigin.x, y ),
 VECTOR2D( gridEndX * gridScreenSize.x + m_gridOrigin.x, y ) );
 }

 // Horizontal lines
 for( int i = gridStartX; i <= gridEndX; i++ )
 {
 const double x = i * gridScreenSize.x + m_gridOrigin.x;

 if( m_axesEnabled && x == 0.0 )
 continue;

 SetLineWidth( ( i % m_gridTick ) ? marker : doubleMarker );
 drawGridLine( VECTOR2D( x, gridStartY * gridScreenSize.y + m_gridOrigin.y ),
 VECTOR2D( x, gridEndY * gridScreenSize.y + m_gridOrigin.y ) );
 }
 }
 else // Dots or Crosses grid
 {
 m_lineWidthIsOdd = true;
 m_isStrokeEnabled = true;

 for( int j = gridStartY; j <= gridEndY; j++ )
 {
 bool tickY = ( j % m_gridTick == 0 );

 for( int i = gridStartX; i <= gridEndX; i++ )
 {
 bool tickX = ( i % m_gridTick == 0 );
 VECTOR2D pos{ i * gridScreenSize.x + m_gridOrigin.x,
 j * gridScreenSize.y + m_gridOrigin.y };

 if( m_gridStyle == GRID_STYLE::SMALL_CROSS )
 {
 SetLineWidth( ( tickX && tickY ) ? doubleMarker : marker );
 drawGridCross( pos );
 }
 else if( m_gridStyle == GRID_STYLE::DOTS )
 {
 double doubleGridLineWidth = m_gridLineWidth * 2.0f;
 drawGridPoint( pos, ( tickX ) ? doubleGridLineWidth : m_gridLineWidth,
 ( tickY ) ? doubleGridLineWidth : m_gridLineWidth );
 }
 }
 }
 }
}