Comprehensive Histogram Support (Issue #49)

README.md

@@ -136,7 +136,7 @@ to build and run them.
 
 **Optional:**
 - `ffmpeg` - Required for saving animations in compressed video formats (MP4, AVI, MKV)
-  - **5-Layer Validation**: Comprehensive framework prevents false positives (Issue #32)
+  - **5-Layer Validation**: Comprehensive framework prevents false positives
   - **External validation**: FFprobe integration for format verification
   - **Documentation**: See [MPEG Validation Guide](doc/mpeg_validation.md) for details
 
@@ -204,7 +204,7 @@ pip install git+https://github.com/lazy-fortran/fortplot.git
 - [x] Interactive display with `show()` (GUI detection for X11, Wayland, macOS, Windows)
 - [x] Animation support with `FuncAnimation` (requires `ffmpeg` for video formats)
   - **5-Layer Validation**: Comprehensive framework with size, header, semantic, and external tool checks
-  - **False Positive Prevention**: Solves Issue #32 with multi-criteria validation
+  - **False Positive Prevention**: Multi-criteria validation framework
 - [x] Unicode and LaTeX-style Greek letters (`\alpha`, `\beta`, `\gamma`, etc.) in all backends
 - [ ] Subplots
 - [ ] Annotations

example/fortran/boxplot_demo.f90.disabled

@@ -30,7 +30,7 @@ program boxplot_demo
     call fig%set_xlabel('Data Groups')
     call fig%set_ylabel('Values')
     call fig%boxplot(normal_data, label='Normal Distribution')
-    call fig%savefig('plots/boxplot_single.png')
+    call fig%savefig('build/example/boxplot_demo/boxplot_single.png')
     print *, 'Created boxplot_single.png'
 
     ! Box plot with outliers
@@ -39,7 +39,7 @@ program boxplot_demo
     call fig%set_xlabel('Data Groups')
     call fig%set_ylabel('Values')
     call fig%boxplot(outlier_data, label='Data with Outliers')
-    call fig%savefig('plots/boxplot_outliers.png')
+    call fig%savefig('build/example/boxplot_demo/boxplot_outliers.png')
     print *, 'Created boxplot_outliers.png'
 
     ! Multiple box plots for comparison
@@ -51,7 +51,7 @@ program boxplot_demo
     call fig%boxplot(group_b, position=2.0_wp, label='Group B')
     call fig%boxplot(group_c, position=3.0_wp, label='Group C')
     call fig%legend()
-    call fig%savefig('plots/boxplot_comparison.png')
+    call fig%savefig('build/example/boxplot_demo/boxplot_comparison.png')
     print *, 'Created boxplot_comparison.png'
 
     ! Horizontal box plot
@@ -60,7 +60,7 @@ program boxplot_demo
     call fig%set_xlabel('Values')
     call fig%set_ylabel('Data Groups')
     call fig%boxplot(normal_data, horizontal=.true., label='Horizontal')
-    call fig%savefig('plots/boxplot_horizontal.png')
+    call fig%savefig('build/example/boxplot_demo/boxplot_horizontal.png')
     print *, 'Created boxplot_horizontal.png'
 
     print *, 'Box plot demonstration completed!'

example/fortran/grid_demo.f90.disabled

@@ -26,7 +26,7 @@ program grid_demo
     call fig%set_title('Basic Grid Lines')
     call fig%set_xlabel('Time (s)')
     call fig%set_ylabel('Amplitude')
-    call fig%savefig('plots/grid_basic.png')
+    call fig%savefig('build/example/grid_demo/grid_basic.png')
     write(*,*) 'Created grid_basic.png'
 
     ! Basic plot with default grid (PDF)
@@ -38,7 +38,7 @@ program grid_demo
     call fig%set_title('Basic Grid Lines')
     call fig%set_xlabel('Time (s)')
     call fig%set_ylabel('Amplitude')
-    call fig%savefig('plots/grid_basic.pdf')
+    call fig%savefig('build/example/grid_demo/grid_basic.pdf')
     write(*,*) 'Created grid_basic.pdf'
 
     ! Grid with custom transparency
@@ -50,7 +50,7 @@ program grid_demo
     call fig%set_title('Grid with Custom Transparency (alpha=0.6)')
     call fig%set_xlabel('Time (s)')
     call fig%set_ylabel('Amplitude')
-    call fig%savefig('plots/grid_custom_alpha.png')
+    call fig%savefig('build/example/grid_demo/grid_custom_alpha.png')
     write(*,*) 'Created grid_custom_alpha.png'
 
     ! Grid with custom line style
@@ -62,7 +62,7 @@ program grid_demo
     call fig%set_title('Grid with Dashed Lines')
     call fig%set_xlabel('Time (s)')
     call fig%set_ylabel('Amplitude')
-    call fig%savefig('plots/grid_dashed.png')
+    call fig%savefig('build/example/grid_demo/grid_dashed.png')
     write(*,*) 'Created grid_dashed.png'
 
     ! X-axis grid only
@@ -74,7 +74,7 @@ program grid_demo
     call fig%set_title('X-Axis Grid Lines Only')
     call fig%set_xlabel('Time (s)')
     call fig%set_ylabel('Amplitude')
-    call fig%savefig('plots/grid_x_only.png')
+    call fig%savefig('build/example/grid_demo/grid_x_only.png')
     write(*,*) 'Created grid_x_only.png'
 
     ! Y-axis grid only
@@ -86,7 +86,7 @@ program grid_demo
     call fig%set_title('Y-Axis Grid Lines Only')
     call fig%set_xlabel('Time (s)')
     call fig%set_ylabel('Amplitude')
-    call fig%savefig('plots/grid_y_only.png')
+    call fig%savefig('build/example/grid_demo/grid_y_only.png')
     write(*,*) 'Created grid_y_only.png'
 
     ! Minor grid lines
@@ -98,7 +98,7 @@ program grid_demo
     call fig%set_title('Minor Grid Lines')
     call fig%set_xlabel('Time (s)')
     call fig%set_ylabel('Amplitude')
-    call fig%savefig('plots/grid_minor.png')
+    call fig%savefig('build/example/grid_demo/grid_minor.png')
     write(*,*) 'Created grid_minor.png'
 
     write(*,*) 'Grid lines demonstration completed!'

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

src/fortplot.f90

@@ -230,9 +230,7 @@ subroutine hist(data, bins, density, label, color)
         real(8), intent(in), optional :: color(3)
 
         call ensure_global_figure_initialized()
-        ! TODO: Implement hist method in figure_core
-        ! call fig%hist(data, bins=bins, density=density, label=label, color=color)
-        call log_error("hist() not yet implemented - please use main branch for histogram support")
+        call fig%hist(data, bins=bins, density=density, label=label, color=color)
     end subroutine hist
 
     subroutine histogram(data, bins, density, label, color)
@@ -258,9 +256,7 @@ subroutine histogram(data, bins, density, label, color)
         real(8), intent(in), optional :: color(3)
 
         call ensure_global_figure_initialized()
-        ! TODO: Implement hist method in figure_core
-        ! call fig%hist(data, bins=bins, density=density, label=label, color=color)
-        call log_error("hist() not yet implemented - please use main branch for histogram support")
+        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)