moved all color depth representation to floating numbers

src/backends/fig_types.f90

@@ -17,8 +17,8 @@ module fig_types
     end interface
 
     type :: canvas_size
-        integer(pixel) :: width
-        integer(pixel) :: height
+        integer :: width
+        integer :: height
     end type canvas_size
 
 contains

src/backends/generic_cairo/cairo_utils.f90

@@ -11,19 +11,14 @@ module fig_cairo_utils
     subroutine set_rgba(cr,color)
         type(c_ptr), intent(inout) :: cr
         type(RGB) :: color
-         call cairo_set_source_rgba(cr,normalize_ch(color%r),normalize_ch(color%g),normalize_ch(color%b),normalize_ch(color%a))
-    end subroutine set_rgba
+        call cairo_set_source_rgba(cr,(color%r),(color%g),(color%b),(color%a))
 
-    function normalize_ch(ch) result(res)
-        integer, intent(in) :: ch
-        real(kind=8) :: res
-        res= real(ch,kind=8)/real(2**rgb_bit_depth-1,kind=8)
-    end function normalize_ch
+    end subroutine set_rgba
 
     subroutine fill(cr,sh)
         type(c_ptr), intent(inout) :: cr
         class(shape), intent(in) :: sh
-        if (sh%fill_color%a .ne. 0) then
+        if (sh%fill_color%a > 0.0001) then
             call set_rgba(cr,sh%fill_color)
             call cairo_fill_preserve(cr)
         end if               
@@ -40,7 +35,7 @@ subroutine stroke(cr,sh)
             deallocate(dash_arr)
         end if
 
-        if (sh%stroke_color%a .ne. 0) then
+        if (sh%stroke_color%a > 0.0001) then
             call set_rgba(cr,sh%stroke_color)
             call cairo_set_line_width(cr,sh%stroke_width)
             call cairo_stroke(cr)

src/fig_config.f90

@@ -1,11 +1,7 @@
 module fig_config
     use iso_fortran_env, only: int32
     implicit none
-    integer, parameter :: rgb_level = int32
-    !! technically it should be int8 but there are problems with signed integers and bit manipulation
-    integer, parameter :: pixel = int32 !! 8 bits per every color channel (r,g,b,a)
     integer, parameter :: rgb_bit_depth = 8
-
     logical :: FIG_ABSOLUTE_COORDINATES = .false.
 end module fig_config
 

src/fig_rgb.f90

@@ -4,30 +4,35 @@ module fig_rgb
 
     type :: RGB
         sequence
-        integer(rgb_level) :: r
-        integer(rgb_level) :: g
-        integer(rgb_level) :: b
-        integer(rgb_level) :: a
+        real(kind=8) :: r
+        real(kind=8) :: g
+        real(kind=8) :: b
+        real(kind=8) :: a
     end type RGB
 
 contains
 
     elemental type(integer(pixel)) function rgb_to_int(color) result(rgb_int)
         type(RGB), intent(in) :: color
+        integer :: r,g,b,a
+        r=color%r*(2**rgb_bit_depth-1)
+        b=color%b*(2**rgb_bit_depth-1)
+        g=color%g*(2**rgb_bit_depth-1)
+        a=color%a*(2**rgb_bit_depth-1)
 
-        rgb_int = ior(ishft(color%a, rgb_bit_depth*3),&
-                  ior(ishft(color%r, rgb_bit_depth*2),&
-                  ior(ishft(color%g, rgb_bit_depth), color%b)))
+        rgb_int = ior(ishft(a, rgb_bit_depth*3),&
+                  ior(ishft(r, rgb_bit_depth*2),&
+                  ior(ishft(g, rgb_bit_depth), b)))
 
      end function rgb_to_int
 
      elemental type(RGB) function int_to_rgb(rgb_int) result(color)
        integer(pixel), intent(in):: rgb_int
 
-       color%a = ibits(rgb_int, 3*rgb_bit_depth, rgb_bit_depth)
-       color%r = ibits(rgb_int, 2*rgb_bit_depth, rgb_bit_depth)
-       color%g = ibits(rgb_int, rgb_bit_depth  , rgb_bit_depth)
-       color%b = ibits(rgb_int, 0, rgb_bit_depth)
+       color%a = real(ibits(rgb_int, 3*rgb_bit_depth, rgb_bit_depth),kind=8) / (2**rgb_bit_depth-1)
+       color%r = real(ibits(rgb_int, 2*rgb_bit_depth, rgb_bit_depth),kind=8) / (2**rgb_bit_depth-1)
+       color%g = real(ibits(rgb_int, rgb_bit_depth  , rgb_bit_depth),kind=8) / (2**rgb_bit_depth-1)
+       color%b = real(ibits(rgb_int, 0, rgb_bit_depth),kind=8) / (2**rgb_bit_depth-1)
      end function int_to_rgb
 
 end module fig_rgb

test/chess.f90

@@ -50,7 +50,7 @@ program chess_checker
     call svg_canva%apply_shapes(checker)
     call svg_canva%save_to_svg()
     call svg_canva%destroy()
-    call bitmap_canva%init(WIDTH,HEIGHT,file_name)
+    call bitmap_canva%init(HEIGHT,WIDTH,file_name)
     call bitmap_canva%apply_shapes(checker)
     call bitmap_canva%save_to_png()
     call bitmap_canva%save_to_ppm()

test/circle.f90

@@ -21,7 +21,7 @@ program circle_test
 
     call canva%init()
     bg = FIG_COLOR_GREEN
-    bg%a = 150
+    bg%a = 150/255.
     call canva%set_background(bg)
 
     ! Circle parameters

test/drawing_test.f90

@@ -34,9 +34,9 @@ program drawing_test_all
     c%center%y = 100.0 / CANVAS_HEIGHT
     c%r = 50.0
     c%fill_color = FIG_COLOR_PINK
-    c%fill_color%a = 100
+    c%fill_color%a = .5
     c%stroke_color = FIG_COLOR_RED
-    c%stroke_color%a = 100
+    c%stroke_color%a = .5
     call canva%add_shape(c)
 
     ! Ellipse
@@ -45,10 +45,10 @@ program drawing_test_all
     elp%rx = 50.0 
     elp%ry = 25.0 
     color = FIG_COLOR_GOLD
-    color%a = 100
+    color%a = .5
     elp%fill_color = color
     elp%stroke_color = FIG_COLOR_RED
-    elp%stroke_color%a = 100
+    elp%stroke_color%a = .5
     call canva%add_shape(elp)
 
     ! Rectangle 1
@@ -57,7 +57,7 @@ program drawing_test_all
     r%width = 100.0 
     r%height = 50.0 
     r%fill_color = FIG_COLOR_BLUE
-    r%fill_color%a = 100
+    r%fill_color%a = .5
     r%stroke_width = 10
     r%stroke_color = FIG_COLOR_GOLD
     call canva%add_shape(r)
@@ -68,12 +68,12 @@ program drawing_test_all
     r%width = 120.0 
     r%height = 50.0 
     r%fill_color = FIG_COLOR_RED
-    r%fill_color%a = 100
+    r%fill_color%a = .5
     r%rx=5
     r%ry=5
     r%stroke_width = 6
     r%stroke_color = FIG_COLOR_SEAGREEN
-    r%stroke_color%a=150
+    r%stroke_color%a=.5
     call canva%add_shape(r)
 
     ! Line
@@ -86,7 +86,7 @@ program drawing_test_all
     call canva%add_shape(l)
     l%stroke_width = 2
     l%stroke_color = FIG_COLOR_RED
-    l%stroke_color%a=100
+    l%stroke_color%a=.5
     call canva%add_shape(l)
 
 
@@ -96,12 +96,12 @@ program drawing_test_all
     l%p2%x = 550.0 / CANVAS_WIDTH
     l%p2%y = 400.0 / CANVAS_HEIGHT
     l%stroke_color = FIG_COLOR_BLACK
-    l%stroke_color%a=100
+    l%stroke_color%a=.5
     l%stroke_width = 50
     call canva%add_shape(l)
     l%stroke_width = 2
     l%stroke_color = FIG_COLOR_RED
-    l%stroke_color%a=100
+    l%stroke_color%a=.5
 
     call canva%add_shape(l)
 
@@ -113,7 +113,7 @@ program drawing_test_all
     ar%start_angle= 0
     ar%end_angle= pi * 1.2
     ar%fill_color = FIG_COLOR_INDIGO
-    ar%fill_color%a=100
+    ar%fill_color%a=.5
     ar%stroke_color = FIG_COLOR_BROWN
     call canva%add_shape(ar)
 

test/int_to_RGB_to_int.f90

@@ -8,22 +8,21 @@ program int_to_RGB_to_int
 
   do color_counter=1,1000
      call random_number(intermediate_real)
-     rgb_old%r = int(256*intermediate_real)     
+     rgb_old%r = intermediate_real
      call random_number(intermediate_real)
-     rgb_old%g = int(256*intermediate_real)
+     rgb_old%g = intermediate_real
      call random_number(intermediate_real)
-     rgb_old%b = int(256*intermediate_real)
+     rgb_old%b = intermediate_real
      call random_number(intermediate_real)
-     rgb_old%a = int(256*intermediate_real)
+     rgb_old%a = intermediate_real
 
      color_integer = rgb_to_int(rgb_old)
-
      rgb_new=int_to_rgb(color_integer)
 
-     if (rgb_old%r /= rgb_new%r .or.  &
-         rgb_old%g /= rgb_new%g .or.  &
-         rgb_old%b /= rgb_new%b .or.  &
-         rgb_old%a /= rgb_new%a ) then
+  if (abs(rgb_old%r - rgb_new%r) > 1.0e-2 .or.  &
+      abs(rgb_old%g - rgb_new%g) > 1.0e-2 .or.  &
+      abs(rgb_old%b - rgb_new%b) > 1.0e-2 .or.  &
+      abs(rgb_old%a - rgb_new%a) > 1.0e-2) then
         error stop "converting between RGB and int or vice versa went wrong"
      endif
 

test/line.f90

@@ -42,9 +42,8 @@ program radial_lines
     angle_step = 1.0 * atan(1.0) / NUM_LINES
 
     do i = 0, NUM_LINES - 1
-        call random_color(color)
         angle = 4 * i * angle_step
-        call draw_radial_line(radial_canvas, cx, cy, radius, angle, color)
+        call draw_radial_line(radial_canvas, cx, cy, radius, angle)
     end do
 
     call svg_canva%init(CANVAS_WIDTH,CANVAS_HEIGHT,file_name)
@@ -60,11 +59,10 @@ program radial_lines
     call test_both(file_name,bitmap_canva)
 contains
 
-    subroutine draw_radial_line(canva, cx, cy, radius, angle, color)
+    subroutine draw_radial_line(canva, cx, cy, radius, angle)
         type(drawing), intent(inout) :: canva
         real, intent(in) :: cx, cy, radius
         real, intent(in) :: angle
-        type(RGB), intent(in) :: color
         integer :: x1, y1, x2, y2
         real :: cos_angle, sin_angle
 
@@ -79,18 +77,5 @@ subroutine draw_radial_line(canva, cx, cy, radius, angle, color)
 
         call canva%add_shape(sh)
     end subroutine draw_radial_line
-
-    subroutine random_color(color)
-        type(RGB), intent(out) :: color
-        real :: r, g, b
-        call random_number(r)
-        call random_number(g)
-        call random_number(b)
-        color%r = int(r * 255)
-        color%g = int(g * 255)
-        color%b = int(b * 255)
-        color%a = 255
-    end subroutine random_color
-
 end program radial_lines
 

test/triangle_pattern.f90

@@ -95,16 +95,5 @@ program test_fig_fill_triangle
 
     call test_both(file_name,bitmap_canva)
 contains 
-    subroutine random_color(color)
-        type(RGB) :: color
-        real :: r, g, b
-        call random_number(r)
-        call random_number(g)
-        call random_number(b)
-        color%r = int(r * 255)
-        color%g = int(g * 255)
-        color%b = int(b * 255)
-        color%a = 255
-    end subroutine random_color
 end program test_fig_fill_triangle