example/modify.f90 added

CHANGELOG.md

@@ -5,6 +5,7 @@ All notable changes to the gtk-fortran project are documented in this file. The
 
 ### Added
 * A `shift()` method to apply a circular shift to a colormap (left is +, right is -).
+ * `example/modify.f90` demonstrates how you can modify a colormap with methods like shift(), in concrete cases.
 * A private `check()` method in the Colormap class. It checks the validity of the colormap and its parameters, prints warnings, and fixes problems if necessary.
 * A `colormaps_list/ForColormap.pdf` manual listing all the available colormaps.
 * A function `bezier(colors, levels)` to create a colormap from continuous Bezier interpolation of control colors, in `src/colormap_class.f90`. The corresponding demo was added in `example/demo.f90`.

example/CMakeLists.txt

@@ -17,3 +17,7 @@ target_link_libraries(extract ${PROJECT_NAME})
 # INFO
 add_executable(info info.f90)
 target_link_libraries(info ${PROJECT_NAME})
+
+# MODIFY
+add_executable(modify modify.f90)
+target_link_libraries(modify ${PROJECT_NAME})

example/README.md

@@ -7,3 +7,4 @@ They can be launched with the command `fpm run --example name_of_the_example` (w
 * `example1.f90` demonstrates how ForImage can be used to import/export PPM files.
 * `extract.f90` demonstrates how to create a specific colormap by extracting a specified number of colors of a colormap.
 * `info.f90` demonstrates how to obtain information about a colormap using the `Colormaps_info` class.
+* `modify.f90` demonstrates how you can modify a colormap with methods like shift(), in concrete cases.

example/modify.f90

@@ -0,0 +1,97 @@
+! The MIT License (MIT)
+!
+! Copyright (c) 2024 Vincent Magnin
+!
+! Permission is hereby granted, free of charge, to any person obtaining a copy
+! of this software and associated documentation files (the "Software"), to deal
+! in the Software without restriction, including without limitation the rights
+! to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+! copies of the Software, and to permit persons to whom the Software is
+! furnished to do so, subject to the following conditions:
+!
+! The above copyright notice and this permission notice shall be included in all
+! copies or substantial portions of the Software.
+!
+! THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+! IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+! FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+! AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+! LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+! OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+! SOFTWARE.
+!-------------------------------------------------------------------------------
+! Contributed by vmagnin: 2024-02-14
+! Last modification: vmagnin 2024-02-15
+!-------------------------------------------------------------------------------
+
+!> This example shows how you can modify a colormap with methods like shift(),
+!> in concrete cases.
+program modify
+ use forcolormap, only: Colormap, wp
+
+ implicit none
+ type(Colormap) :: cmap
+
+ !> In the Scientific colour maps collection, all cyclic colormaps have their
+ !> bright part in the middle. But we can shift the dark part towards the
+ !> center.
+ call cmap%set("bamO", 0.0_wp, 2.0_wp)
+ call cmap%colorbar("bamO", encoding='binary')
+ call cmap%shift(cmap%get_levels() / 2)
+ call cmap%colorbar("bamO_shifted", encoding='binary')
+ print *, "See the bamO.ppm and bamO_shifted.ppm colorbars"
+
+ !> In the Scientific colour maps collection, all categorical colormaps
+ !> begin with a dark colour, but a shift can be applied to begin with a
+ !> brighter colour.
+ call cmap%set("actonS", 0.0_wp, 2.0_wp)
+ call cmap%colorbar("actonS", encoding='binary')
+ call cmap%shift(+2) !! Two levels towards left
+ call cmap%colorbar("actonS_shifted", encoding='binary')
+ print *, "See the actonS.ppm and actonS_shifted.ppm colorbars"
+
+ !> Starting from a diverging colormap, we can obtain what could be called
+ !> a diverging multi-sequential colormap.
+ call cmap%set("bam", 0.0_wp, 2.0_wp)
+ call cmap%colorbar("bam", encoding='binary')
+ call cmap%shift(cmap%get_levels() / 2)
+ call cmap%colorbar("bam_shifted", encoding='binary')
+ print *, "See the bam.ppm and bam_shifted.ppm colorbars"
+
+ contains
+
+ subroutine test_colormap(self, filename, encoding)
+ use forimage, only: format_pnm
+ type(Colormap), intent(inout) :: self
+ character(*), intent(in) :: filename
+ integer :: k, j ! Pixbuffer coordinates
+ integer, parameter :: pixwidth = 600
+ integer, parameter :: pixheight = 600
+ integer, dimension(pixheight,pixwidth*3) :: rgb_image
+ integer :: red, green, blue
+ real(wp) :: z
+ type(format_pnm) :: ppm
+ character(*), intent(in) :: encoding
+
+ do k = 0, pixwidth-1
+ do j = 0, pixheight-1
+ ! Computing a z=f(x,y) function:
+ z = 1.0_wp + sin(k*j/10000.0_wp) * cos(j/100.0_wp)
+ ! The corresponding RGB values in our colormap:
+ call self%compute_RGB(z, red, green, blue)
+ rgb_image(pixheight-j, 3*(k+1)-2) = red
+ rgb_image(pixheight-j, 3*(k+1)-1) = green
+ rgb_image(pixheight-j, 3*(k+1)) = blue 
+ end do
+ end do
+
+ call ppm%set_pnm(encoding = encoding,&
+ file_format = 'ppm',&
+ width = pixwidth,&
+ height = pixheight,&
+ max_color = 255,&
+ comment = 'comment',&
+ pixels = rgb_image)
+ call ppm%export_pnm(filename)
+ end subroutine test_colormap
+end program modify

fpm.toml

@@ -42,6 +42,11 @@ name = "extract"
 source-dir = "example"
 main = "extract.f90"
 
+[[example]]
+name = "modify"
+source-dir = "example"
+main = "modify.f90"
+
 [build]
 auto-executables = true
 auto-tests = true