/**
 * Draw labelled ticks on a line. Ticks are spaced according to a
 * maximum density. Miror ticks are not labelled.
 *
 * @param aGal the GAL to draw on
 * @param aOrigin start of line to draw ticks on
 * @param aLine line vector
 * @param aMinorTickLen length of minor ticks in IU
 */
void drawTicksAlongLine( KIGFX::GAL& aGal, const VECTOR2D& aOrigin,
        const VECTOR2D& aLine, double aMinorTickLen )
{
    VECTOR2D tickLine = aLine.Rotate( -M_PI_2 );

    double tickSpace;
    TICK_FORMAT tickF = getTickFormatForScale( aGal.GetWorldScale(), tickSpace );

    // number of ticks in whole ruler
    int numTicks = (int) std::ceil( aLine.EuclideanNorm() / tickSpace );

    // work out which way up the tick labels go
    double labelAngle = -tickLine.Angle();

    if( aLine.Angle() > 0 )
    {
        aGal.SetHorizontalJustify( GR_TEXT_HJUSTIFY_LEFT );
    }
    else
    {
        aGal.SetHorizontalJustify( GR_TEXT_HJUSTIFY_RIGHT );
        labelAngle += M_PI;
    }

    // text and ticks are dimmed
    aGal.SetStrokeColor( PreviewOverlayDefaultColor().WithAlpha( PreviewOverlayDeemphAlpha( true ) ) );

    const auto labelOffset = tickLine.Resize( aMinorTickLen * ( majorTickLengthFactor + 1 ) );

    for( int i = 0; i < numTicks; ++i )
    {
        const auto tickPos = aOrigin + aLine.Resize( tickSpace * i );

        double length = aMinorTickLen;
        bool drawLabel = false;

        if( i % tickF.majorStep == 0)
        {
            drawLabel = true;
            length *= majorTickLengthFactor;
        }
        else if( tickF.midStep && i % tickF.midStep == 0 )
        {
            drawLabel = true;
            length *= midTickLengthFactor;
        }

        aGal.DrawLine( tickPos, tickPos + tickLine.Resize( length ) );

        if( drawLabel )
        {
            wxString label = DimensionLabel( "", tickSpace * i, g_UserUnit );

            // FIXME: spaces choke OpenGL lp:1668455
            label.erase( std::remove( label.begin(), label.end(), ' ' ), label.end() );

            aGal.BitmapText( label, tickPos + labelOffset, labelAngle );
        }
    }
}
void SIMPLE_OVERLAY_ITEM::setupGal( KIGFX::GAL& aGal ) const
{
    // default impl: set up the GAL options we have - the
    // overriding class can add to this if needed
    aGal.SetLineWidth( m_lineWidth );
    aGal.SetStrokeColor( m_strokeColor );
    aGal.SetFillColor( m_fillColor );
    aGal.SetIsStroke( true );
    aGal.SetIsFill( true );
}