feat: Add histogram plotting support (#49)

.github/workflows/ci.yml

@@ -78,4 +78,4 @@ jobs:
         cd build
         cmake ..
         make
-        ./fortplotlib_test
+        ./fortplot_test

Makefile

@@ -104,6 +104,7 @@ create_build_dirs:
 	@mkdir -p build/example/smart_show_demo
 	@mkdir -p build/example/animation
 	@mkdir -p build/example/stateful_streamplot
+	@mkdir -p build/example/histogram_demo
 	@mkdir -p build/example/subplot_demo
 
 # Help target

README.md

@@ -1,7 +1,7 @@
 # ![fortplot logo](media/logo.jpg)
 
-[![codecov](https://codecov.io/gh/krystophny/fortplot/branch/main/graph/badge.svg)](https://codecov.io/gh/krystophny/fortplot)
-[![Documentation](https://img.shields.io/badge/docs-FORD-blue.svg)](https://krystophny.github.io/fortplot/)
+[![codecov](https://codecov.io/gh/lazy-fortran/fortplot/branch/main/graph/badge.svg)](https://codecov.io/gh/lazy-fortran/fortplot)
+[![Documentation](https://img.shields.io/badge/docs-FORD-blue.svg)](https://lazy-fortran.github.io/fortplot/)
 
 Fortran-native plotting inspired by Python's `matplotlib.pyplot` and https://github.com/jacobwilliams/pyplot-fortran . This library is under active development and API still subject to change. There are no external dependencies. Ironically, it has also Python interface installable via `pip` (see below) `fortplot.fortplot` that can be used as a drop-in replacement for `matplotlib.pyplot` for a limited set of features.
 
@@ -111,7 +111,7 @@ to build and run them.
 Add to your `fpm.toml`:
 ```toml
 [[dependencies]]
-fortplot = { git = "https://github.com/krystophny/fortplot" }
+fortplot = { git = "https://github.com/lazy-fortran/fortplot" }
 ```
 
 ### For CMake projects
@@ -122,7 +122,7 @@ include(FetchContent)
 
 FetchContent_Declare(
     fortplot
-    GIT_REPOSITORY https://github.com/krystophny/fortplot
+    GIT_REPOSITORY https://github.com/lazy-fortran/fortplot
     GIT_TAG        main
 )
 FetchContent_MakeAvailable(fortplot)
@@ -134,7 +134,7 @@ target_link_libraries(your_target fortplot::fortplot)
 Install the Python package with pip:
 
 ```bash
-pip install git+https://github.com/krystophny/fortplot.git
+pip install git+https://github.com/lazy-fortran/fortplot.git
 ```
 
 ## Features
@@ -146,7 +146,7 @@ pip install git+https://github.com/krystophny/fortplot.git
 - [x] Streamplots (`streamplot`) for vector field visualization
 - [ ] Scatter plots (`scatter`)
 - [ ] Bar charts (`bar`)
-- [ ] Histograms (`hist`)
+- [x] Histograms (`hist`)
 - [ ] Images (`imshow`)
 
 ### Backends

doc/cmake_example/CMakeLists.txt

@@ -7,19 +7,19 @@ enable_language(Fortran)
 # Include FetchContent module
 include(FetchContent)
 
-# Fetch and build fortplotlib using CMake
+# Fetch and build fortplot using CMake
 FetchContent_Declare(
-    fortplotlib
-    GIT_REPOSITORY https://github.com/krystophny/fortplot
+    fortplot
+    GIT_REPOSITORY https://github.com/lazy-fortran/fortplot
     GIT_TAG main
 )
-FetchContent_MakeAvailable(fortplotlib)
+FetchContent_MakeAvailable(fortplot)
 
 # Create a simple test program
 add_executable(fortplot_test main.f90)
 
-# Link against fortplotlib (using old name until rename is merged to main)
-target_link_libraries(fortplot_test fortplotlib::fortplotlib)
+# Link against fortplot
+target_link_libraries(fortplot_test fortplot::fortplot)
 
 # Set Fortran compiler flags
 set(CMAKE_Fortran_FLAGS "-Wall -Wextra -fimplicit-none")

doc/fpm_example/fpm.toml

@@ -3,5 +3,5 @@ version = "0.1.0"
 license = "MIT"
 
 [dependencies]
-fortplot = { path = "../.." }
+fortplot = { git = "https://github.com/lazy-fortran/fortplot" }
 

doc/python_example/pyproject.toml

@@ -6,6 +6,6 @@ build-backend = "setuptools.build_meta"
 name = "fortplot-example"
 version = "0.1.0"
 dependencies = [
-    "fortplot @ git+https://github.com/krystophny/fortplot.git",
+    "fortplot @ git+https://github.com/lazy-fortran/fortplot.git",
     "numpy"
 ]

example/fortran/basic_plots/README.md

@@ -31,4 +31,4 @@ The example generates the following output files:
 - `simple_plot.png` - Simple sine wave visualization
 - `multi_line.png` - Multiple functions on the same plot
 
-See the [documentation gallery](https://krystophny.github.io/fortplot/) for visual examples.
+See the [documentation gallery](https://lazy-fortran.github.io/fortplot/) for visual examples.

example/fortran/colored_contours/README.md

@@ -54,4 +54,4 @@ The example generates the following output files:
 - `saddle_plasma.pdf` - Vector format of the saddle point
 - `saddle_plasma.txt` - ASCII art of the saddle point pattern
 
-See the [documentation gallery](https://krystophny.github.io/fortplot/) for visual examples.
+See the [documentation gallery](https://lazy-fortran.github.io/fortplot/) for visual examples.

example/fortran/contour_demo/README.md

@@ -34,4 +34,4 @@ The example generates the following output files:
 - `mixed_plot.pdf` - Vector format of the mixed plot
 - `mixed_plot.txt` - ASCII art representation of the mixed plot
 
-See the [documentation gallery](https://krystophny.github.io/fortplot/) for visual examples.
+See the [documentation gallery](https://lazy-fortran.github.io/fortplot/) for visual examples.

example/fortran/histogram_demo.f90

@@ -0,0 +1,66 @@
+program histogram_demo
+    !! Example demonstrating histogram plotting capabilities
+    !! Shows basic histogram, custom bins, and density normalization
+
+    use, intrinsic :: iso_fortran_env, only: wp => real64
+    use fortplot
+    implicit none
+
+    integer, parameter :: n_data = 1000
+    real(wp) :: data(n_data), normal_data(n_data)
+    type(figure_t) :: fig
+    integer :: i
+    real(wp) :: pi = 3.14159265359_wp
+
+    ! Generate random-like data (simple distribution)
+    do i = 1, n_data
+        data(i) = real(i, wp) / 100.0_wp + sin(real(i, wp) * 0.01_wp) * 5.0_wp
+    end do
+
+    ! Generate normal-like data using Box-Muller transform approximation
+    do i = 1, n_data
+        normal_data(i) = cos(2.0_wp * pi * real(i, wp) / real(n_data, wp)) * &
+                        sqrt(-2.0_wp * log(max(real(mod(i, 1000), wp) / 1000.0_wp, 0.001_wp)))
+    end do
+
+    ! Basic histogram
+    call fig%initialize(800, 600)
+    call fig%hist(data)
+    call fig%set_title('Basic Histogram Example')
+    call fig%set_xlabel('Value')
+    call fig%set_ylabel('Frequency')
+    call fig%savefig('build/example/histogram_demo/histogram_basic.png')
+    write(*,*) 'Created histogram_basic.png'
+
+    ! Custom bins histogram  
+    call fig%initialize(800, 600)
+    call fig%hist(data, bins=20)
+    call fig%set_title('Histogram with 20 Bins')
+    call fig%set_xlabel('Value')
+    call fig%set_ylabel('Frequency')
+    call fig%savefig('build/example/histogram_demo/histogram_custom_bins.png')
+    write(*,*) 'Created histogram_custom_bins.png'
+
+    ! Density histogram
+    call fig%initialize(800, 600)
+    call fig%hist(normal_data, bins=15, density=.true.)
+    call fig%set_title('Normalized Histogram (Density)')
+    call fig%set_xlabel('Value')
+    call fig%set_ylabel('Probability Density')
+    call fig%savefig('build/example/histogram_demo/histogram_density.png')
+    write(*,*) 'Created histogram_density.png'
+
+    ! Multiple histograms with labels
+    call fig%initialize(800, 600)
+    call fig%hist(data(1:500), bins=15, label='Dataset 1', color=[0.0_wp, 0.447_wp, 0.698_wp])
+    call fig%hist(normal_data(1:500), bins=15, label='Dataset 2', color=[0.835_wp, 0.369_wp, 0.0_wp])
+    call fig%legend()
+    call fig%set_title('Multiple Histograms')
+    call fig%set_xlabel('Value')
+    call fig%set_ylabel('Frequency')
+    call fig%savefig('build/example/histogram_demo/histogram_multiple.png')
+    write(*,*) 'Created histogram_multiple.png'
+
+    write(*,*) 'Histogram demonstration completed!'
+
+end program histogram_demo

example/fortran/line_styles/README.md

@@ -37,4 +37,4 @@ The example generates the following output files:
 - `line_styles.pdf` - Vector format of the same visualization
 - `line_styles.txt` - ASCII art representation of the line styles
 
-See the [documentation gallery](https://krystophny.github.io/fortplot/) for visual examples.
+See the [documentation gallery](https://lazy-fortran.github.io/fortplot/) for visual examples.

example/fortran/marker_demo/README.md

@@ -51,4 +51,4 @@ The example generates the following output files:
 - `marker_colors.pdf` - Vector format of colored markers
 - `marker_colors.txt` - ASCII art with different marker representations
 
-See the [documentation gallery](https://krystophny.github.io/fortplot/) for visual examples.
+See the [documentation gallery](https://lazy-fortran.github.io/fortplot/) for visual examples.

example/fortran/pcolormesh_demo/README.md

@@ -44,4 +44,4 @@ The example generates the following output files:
 - `pcolormesh_sinusoidal.pdf` - Vector format of the sinusoidal pattern
 - `pcolormesh_sinusoidal.txt` - ASCII representation of the sine wave pattern
 
-See the [documentation gallery](https://krystophny.github.io/fortplot/) for visual examples.
+See the [documentation gallery](https://lazy-fortran.github.io/fortplot/) for visual examples.

example/fortran/scale_examples/README.md

@@ -34,4 +34,4 @@ The example generates the following output files:
 - `symlog_scale.pdf` - Vector format of the symlog scale plot
 - `symlog_scale.txt` - ASCII art representation with symmetric log axes
 
-See the [documentation gallery](https://krystophny.github.io/fortplot/) for visual examples.
+See the [documentation gallery](https://lazy-fortran.github.io/fortplot/) for visual examples.

example/generate_example_docs.f90

@@ -199,17 +199,17 @@ subroutine write_source_links(unit_out, example_name)
         select case(example_name)
         case('animation')
             fortran_file = 'save_animation_demo.f90'
-            fortran_path = 'https://github.com/krystophny/fortplot/blob/main/example/fortran/' // &
+            fortran_path = 'https://github.com/lazy-fortran/fortplot/blob/main/example/fortran/' // &
                            trim(example_name) // '/' // trim(fortran_file)
             local_fortran_path = 'example/fortran/' // trim(example_name) // '/' // trim(fortran_file)
         case('ascii_heatmap')
             fortran_file = 'ascii_heatmap_demo.f90'
-            fortran_path = 'https://github.com/krystophny/fortplot/blob/main/example/fortran/' // &
+            fortran_path = 'https://github.com/lazy-fortran/fortplot/blob/main/example/fortran/' // &
                            trim(example_name) // '/' // trim(fortran_file)
             local_fortran_path = 'example/fortran/' // trim(example_name) // '/' // trim(fortran_file)
         case default
             fortran_file = trim(example_name) // '.f90'
-            fortran_path = 'https://github.com/krystophny/fortplot/blob/main/example/fortran/' // &
+            fortran_path = 'https://github.com/lazy-fortran/fortplot/blob/main/example/fortran/' // &
                            trim(example_name) // '/' // trim(fortran_file)
             local_fortran_path = 'example/fortran/' // trim(example_name) // '/' // trim(fortran_file)
         end select
@@ -229,7 +229,7 @@ subroutine write_source_links(unit_out, example_name)
         if (python_exists) then
             write(unit_out, '(A)') ''
             write(unit_out, '(A)') '🐍 **Python:** [' // trim(example_name) // &
-                                   '.py](https://github.com/krystophny/fortplot/blob/main/' // &
+                                   '.py](https://github.com/lazy-fortran/fortplot/blob/main/' // &
                                    trim(python_path) // ')'
         end if
         write(unit_out, '(A)') ''

scripts/generate_example_docs.py

@@ -91,15 +91,15 @@ def generate_example_page(example_info, output_dir):
         content += "### PDF Output\n\n"
         for pdf in pdf_files:
             pdf_name = Path(pdf).name
-            content += f"- [{pdf_name}](https://github.com/krystophny/fortplot/blob/main/{pdf})\n"
+            content += f"- [{pdf_name}](https://github.com/lazy-fortran/fortplot/blob/main/{pdf})\n"
         content += "\n"
 
     # Add link back to source
     rel_source = os.path.relpath(source_file, '.')
     content += f"""
 ---
 
-Source: [{rel_source}](https://github.com/krystophny/fortplot/blob/main/{rel_source})
+Source: [{rel_source}](https://github.com/lazy-fortran/fortplot/blob/main/{rel_source})
 """
 
     # Write the markdown file

src/fortplot.f90

@@ -26,6 +26,7 @@ module fortplot
     ! Re-export public interface
     public :: figure_t, wp
     public :: plot, contour, contour_filled, pcolormesh, streamplot, boxplot, show, show_viewer
+    public :: hist, histogram
     public :: xlabel, ylabel, title, legend
     public :: savefig, figure
     public :: add_plot, add_contour, add_contour_filled, add_pcolormesh
@@ -164,6 +165,57 @@ subroutine streamplot(x, y, u, v, density)
         call fig%streamplot(x, y, u, v, density=density)
     end subroutine streamplot
 
+    subroutine hist(data, bins, density, label, color)
+        !! Add histogram plot to the global figure (pyplot-style)
+        !!
+        !! Creates a histogram from input data, compatible with matplotlib.pyplot.hist
+        !!
+        !! Arguments:
+        !!   data: Input data array to create histogram from
+        !!   bins: Optional - number of bins (integer, default: 10)
+        !!   density: Optional - normalize to probability density (default: false)
+        !!   label: Optional - histogram label for legend
+        !!   color: Optional - histogram color as RGB values [0-1]
+        !!
+        !! Example:
+        !!   ! Simple histogram
+        !!   call hist(data_values, bins=20, label='Distribution')
+        real(8), intent(in) :: data(:)
+        integer, intent(in), optional :: bins
+        logical, intent(in), optional :: density
+        character(len=*), intent(in), optional :: label
+        real(8), intent(in), optional :: color(3)
+
+        call ensure_global_figure_initialized()
+        call fig%hist(data, bins=bins, density=density, label=label, color=color)
+    end subroutine hist
+
+    subroutine histogram(data, bins, density, label, color)
+        !! Add histogram plot to the global figure (pyplot-style)
+        !!
+        !! Alias for hist() subroutine - creates a histogram from input data
+        !! Compatible with matplotlib.pyplot.histogram
+        !!
+        !! Arguments:
+        !!   data: Input data array to create histogram from
+        !!   bins: Optional - number of bins (integer, default: 10)
+        !!   density: Optional - normalize to probability density (default: false)
+        !!   label: Optional - histogram label for legend
+        !!   color: Optional - histogram color as RGB values [0-1]
+        !!
+        !! Example:
+        !!   ! Simple histogram
+        !!   call histogram(data_values, bins=20, label='Distribution')
+        real(8), intent(in) :: data(:)
+        integer, intent(in), optional :: bins
+        logical, intent(in), optional :: density
+        character(len=*), intent(in), optional :: label
+        real(8), intent(in), optional :: color(3)
+
+        call ensure_global_figure_initialized()
+        call fig%hist(data, bins=bins, density=density, label=label, color=color)
+    end subroutine histogram
+
     subroutine boxplot(data, position, width, label, show_outliers, horizontal, color)
         !! Add a box plot to the global figure (matplotlib-style)
         !!
@@ -544,4 +596,12 @@ subroutine show_viewer(blocking)
         call show_viewer_implementation(blocking=blocking)
     end subroutine show_viewer
 
+    subroutine ensure_global_figure_initialized()
+        !! Ensure global figure is initialized before use (matplotlib compatibility)
+        !! Auto-initializes with default dimensions if not already initialized
+        if (.not. allocated(fig%backend)) then
+            call fig%initialize()
+        end if
+    end subroutine ensure_global_figure_initialized
+
 end module fortplot

src/fortplot_figure.f90

@@ -9,7 +9,8 @@ module fortplot_figure
     !! Re-exports: utility functions from fortplot_utils
 
     use fortplot_figure_core, only: figure_t, plot_data_t, PLOT_TYPE_LINE, &
-                                    PLOT_TYPE_CONTOUR, PLOT_TYPE_PCOLORMESH, PLOT_TYPE_BOXPLOT
+                                   PLOT_TYPE_CONTOUR, PLOT_TYPE_PCOLORMESH, &
+                                   PLOT_TYPE_HISTOGRAM, PLOT_TYPE_BOXPLOT
     use fortplot_scales, only: apply_scale_transform, apply_inverse_scale_transform, &
                               transform_x_coordinate, transform_y_coordinate
     use fortplot_utils, only: get_backend_from_filename, initialize_backend
@@ -19,7 +20,8 @@ module fortplot_figure
 
     ! Re-export all public entities for backward compatibility
     public :: figure_t, plot_data_t
-    public :: PLOT_TYPE_LINE, PLOT_TYPE_CONTOUR, PLOT_TYPE_PCOLORMESH, PLOT_TYPE_BOXPLOT
+    public :: PLOT_TYPE_LINE, PLOT_TYPE_CONTOUR, PLOT_TYPE_PCOLORMESH, &
+              PLOT_TYPE_HISTOGRAM, PLOT_TYPE_BOXPLOT
     public :: apply_scale_transform, apply_inverse_scale_transform
     public :: transform_x_coordinate, transform_y_coordinate
     public :: get_backend_from_filename, initialize_backend