fix: reset plot_count unconditionally during figure initialization

BACKLOG.md

@@ -9,7 +9,7 @@
 - [x] #334: Fix - No output visible on pcolormesh_demo.html (COMPLETED - PR #351)
 - [x] #333: Fix - Circles seem not centered with line plot in marker_demo.html (COMPLETED)
 - [x] #332: Fix - Dashed and dash-dotted look funny on line_styles.html (COMPLETED)
-- [ ] #330: Fix - Old plot not cleared in second figure (figure() call) in contour_demo.html
+- [x] #330: Fix - Old plot not cleared in second figure (figure() call) in contour_demo.html (COMPLETED)
 - [ ] #329: Fix - No output visible on colored_contours.html
 - [ ] #328: Fix - One legend entry too much in basic_plots.html second plot
 - [ ] #327: Fix - MP4 link not showing on animation.html
@@ -24,6 +24,7 @@
 - [ ] #350: Refactor - improve documentation comments in raster drawing module
 
 ## DOING (Current Work)
+- [ ] #330: Fix - Old plot not cleared in second figure (figure() call) in contour_demo.html
 
 ## BLOCKED (Infrastructure Issues)
 

src/fortplot_figure_core.f90

@@ -146,8 +146,8 @@ subroutine initialize(self, width, height, backend)
 
         if (.not. allocated(self%plots)) then
             allocate(self%plots(self%max_plots))
-            self%plot_count = 0  ! Only reset plot count when allocating plots array
         end if
+        self%plot_count = 0  ! Reset plot count on every figure() call
         self%rendered = .false.
 
         ! Preserve existing legend settings during re-initialization

test/test_figure_clear_330.f90

@@ -0,0 +1,38 @@
+program test_figure_clear
+    !> Test case for Issue #330: Ensure figure() properly clears previous plots
+    !> This test validates that plot_count is reset when figure() is called multiple times
+
+    use fortplot
+    use iso_fortran_env, only: real64
+    implicit none
+
+    real(real64) :: x(5) = [1.0_real64, 2.0_real64, 3.0_real64, 4.0_real64, 5.0_real64]
+    real(real64) :: y1(5) = [1.0_real64, 4.0_real64, 2.0_real64, 3.0_real64, 5.0_real64]
+    real(real64) :: y2(5) = [2.0_real64, 3.0_real64, 1.0_real64, 5.0_real64, 4.0_real64]
+
+    print *, 'Testing figure clearing functionality...'
+
+    ! First figure - should have 1 plot
+    call figure()
+    call plot(x, y1)
+    print *, 'First figure created with 1 plot'
+
+    ! Second figure - should clear previous plot and have only 1 plot
+    call figure()
+    call plot(x, y2)
+    print *, 'Second figure created - previous plot should be cleared'
+
+    ! Test with multiple plots in sequence
+    call figure()
+    call plot(x, y1, label='Line 1')
+    call plot(x, y2, label='Line 2') 
+    print *, 'Third figure with 2 plots'
+
+    ! Clear and add single plot again
+    call figure()
+    call plot(x, y1)
+    print *, 'Fourth figure - should have only 1 plot, not accumulating previous plots'
+
+    print *, 'Figure clearing test completed successfully'
+
+end program test_figure_clear