1 files changed, 173 insertions, 0 deletions
diff --git a/render.f90 b/render.f90
new file mode 100644
index 0000000..2913507
--- /dev/null
+++ b/render.f90
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+module render
+implicit none
+
+    type, abstract :: renderer
+    
+        integer::y
+        integer::max_width
+        
+        contains
+        
+        procedure::render_proportional
+        
+        procedure(initialize), deferred::initialize
+        
+        procedure(calculate_width), deferred::text_width
+        procedure(calculate_height), deferred::text_height
+        procedure(calculate_visibility), deferred::is_text_visible
+        procedure(draw_text), deferred::draw_porportional
+
+        procedure(calculate_width), deferred::preformatted_width
+        procedure(calculate_height), deferred::preformatted_height
+        procedure(calculate_visibility), deferred::is_preformatted_visible
+        procedure(draw_text), deferred::draw_preformatted
+
+    end type renderer
+
+    abstract interface
+        subroutine initialize(self)
+        import::renderer
+        class(renderer)::self
+        end subroutine initialize
+    end interface
+
+    abstract interface
+        function calculate_width(self, text)
+        import::renderer
+        class(renderer)::self
+        character(*), intent(in)::text
+        integer::calculate_width
+        end function calculate_width
+    end interface
+    
+    abstract interface
+        function calculate_height(self, text)
+        import::renderer
+        class(renderer)::self
+        character(*), intent(in)::text
+        integer::calculate_height
+        end function calculate_height
+    end interface
+    
+    abstract interface
+        subroutine draw_text(self, text)
+        import::renderer
+        class(renderer)::self
+        character(*), intent(in)::text
+        end subroutine draw_text
+    end interface
+    
+    abstract interface
+        function calculate_visibility(self, text)
+        import::renderer
+        class(renderer)::self
+        character(*), intent(in)::text
+        logical::calculate_visibility
+        end function calculate_visibility
+    end interface
+
+contains
+ 
+    function width_of_line(r, text, startpos, endpos)
+    implicit none
+    
+        class(renderer)::r
+        character(*), intent(in)::text
+        integer, intent(in)::startpos, endpos
+        integer::width_of_line
+        
+        integer::my_start, my_end
+        
+        my_end = endpos
+        if(endpos <= 0) then
+            my_end = len_trim(text)
+        end if
+        
+        my_start = startpos
+        if(startpos <= 0) then
+            my_start = 1
+        end if
+        
+        if(my_end <= my_start) then
+            width_of_line = 0
+        else
+            width_of_line = r%text_width(text(my_start:my_end))
+        end if
+    
+    end function width_of_line
+
+    function wrap_line(r, text, startpos) result(endpos)
+    implicit none
+
+        class(renderer)::r
+        character(*), intent(in)::text
+        integer, intent(in)::startpos
+        integer::endpos
+        integer::my_start
+        integer::w
+        
+        my_start = startpos
+        if(startpos == 0) then
+            my_start = 1
+        end if
+        
+        endpos = len_trim(text)
+        w = width_of_line(r, text, my_start, endpos)
+        do while(w > r%max_width)
+        
+            endpos = endpos - 1
+            do while(text(endpos:endpos) /= ' ' .and. text(endpos:endpos) /= '-')
+                endpos = endpos - 1
+            end do
+            
+            w = width_of_line(r, text, my_start, endpos)
+        end do
+        
+    end function wrap_line
+    
+    subroutine render_proportional(r, text)
+    implicit none
+    
+        class(renderer)::r
+        character(*)::text
+        
+        integer::startpos, endpos
+        
+        if(len_trim(text) == 0) then 
+            if(r%is_text_visible(" ")) then
+                call r%draw_porportional("")
+            end if
+            r%y = r%y + r%text_height(" ")
+        else
+            startpos = 1
+            endpos = wrap_line(r, text, startpos)
+            do while(endpos > startpos)
+                if(r%is_text_visible(text(startpos:endpos))) then
+                    call r%draw_porportional(text(startpos:endpos))
+                end if
+                r%y = r%y + r%text_height(text(startpos:endpos))
+                
+                ! Advance string positions
+                startpos = endpos+1
+                do while(text(startpos:startpos) == ' ')
+                    startpos = startpos + 1
+                end do
+                endpos = wrap_line(r, text, startpos)
+            end do
+        end if
+    
+    end subroutine render_proportional
+    
+    subroutine render_preformatted(r, text)
+    implicit none
+    
+        class(renderer)::r
+        character(*)::text
+        
+        if(r%is_preformatted_visible(text)) then
+            call r%draw_preformatted(text)
+        end if
+        r%y = r%y + r%preformatted_height(text)
+    
+    end subroutine render_preformatted
+end module render