PLOT and SURFACE xdl-charts Integration

Overview

The traditional PLOT and SURFACE procedures have been enhanced to use the modern xdl-charts/Tauri system by default, with automatic fallback to the original graphics rendering when Tauri is unavailable.

What Changed

Before

  • PLOT and SURFACE generated static PNG images
  • Required GUI callbacks for interactive display
  • Limited interactivity
  • 2D surface rendering for 3D plots

After

  • Default: Interactive Tauri windows with ECharts rendering
  • Fallback: Original PNG generation if Tauri unavailable
  • Full 3D interactivity with rotation, zoom, pan
  • WebGL acceleration for large datasets
  • Modern web-based charting

Usage

No code changes required! Existing scripts continue to work:

; Simple line plot
x = FINDGEN(100) / 10.0
y = SIN(x)
PLOT, x, y

; Auto-generate X coordinates
y2 = COS(x)
PLOT, y2

; 3D surface plot
z = FLTARR(40, 40)
FOR i=0, 39 DO FOR j=0, 39 DO BEGIN
  z[i,j] = SIN(SQRT((i-20)^2 + (j-20)^2) / 5.0)
ENDFOR
SURFACE, z

Benefits

  1. Better Interactivity: Tauri windows provide native desktop integration
  2. 3D Support: True 3D rendering with ECharts GL
  3. Performance: WebGL acceleration for large datasets
  4. Backwards Compatible: Automatic fallback ensures old scripts work
  5. Modern UI: Clean, responsive charts with built-in controls

Fallback Behavior

If xdl-chart-viewer is not available or fails to launch:

  • Logs a message to stderr: "PLOT: xdl-charts unavailable (...), using fallback renderer"
  • Automatically uses original graphics::plot_2d/surface_plot
  • Generates PNG files as before
  • Works with GUI callbacks if registered

Architecture 

PLOT/SURFACE procedure
  ↓
try_chart_plot / try_surface3d (xdl-charts)
  ↓
  Success? → Open Tauri window → Return
  ↓
  Failure? → Log error → Continue
  ↓
graphics::plot_2d / surface_plot (fallback)
  ↓
Generate PNG file → Try GUI callbacks → Return

Implementation Details

Code Locations

  • Main procedures: xdl-stdlib/src/graphics_procs.rs
    • plot_with_keywords() - Enhanced PLOT procedure
    • surface() - Enhanced SURFACE procedure
    • try_chart_plot() - xdl-charts helper for PLOT
    • try_surface3d() - xdl-charts helper for SURFACE
  • Charting backend: xdl-stdlib/src/charting_procs.rs
    • plot() - ECharts line chart generator
    • surface3d() - ECharts 3D surface generator

Key Functions

try_chart_plot(x_data, y_data, title) -> Result<(), XdlError>

  • Converts arrays to XdlValue
  • Calls charting_procs::plot()
  • Returns error if unavailable (triggers fallback)

try_surface3d(z_data, title) -> Result<(), XdlError>

  • Converts 2D array to XdlValue
  • Calls charting_procs::surface3d()
  • Returns error if unavailable (triggers fallback)

Testing

Run the test script:

./target/release/xdl examples/charting/test_plot_surface.xdl

Expected output:

  • 3 Tauri windows open (2 line plots, 1 surface plot)
  • Interactive charts with zoom, pan, rotation
  • No fallback messages (if xdl-chart-viewer is available)

Future Enhancements

Potential improvements:

  1. Support keyword arguments (TITLE, XTITLE, YTITLE) in xdl-charts
  2. Add CONTOUR procedure support
  3. Multi-series plotting in single window
  4. Export charts from Tauri window (PNG, SVG, PDF)
  5. Real-time data updates

Compatibility

  • ✅ Maintains full backward compatibility
  • ✅ Works with existing XDL/IDL scripts
  • ✅ No breaking changes
  • ✅ Graceful degradation when Tauri unavailable
  • ✅ Preserves GUI callback system for custom integrations

New charting procedures that use xdl-charts directly:

  • CHART_PLOT - Direct access to ECharts line plotting
  • CHART_SCATTER - Scatter plots
  • CHART_BAR - Bar charts
  • SURFACE3D - Direct 3D surface plotting
  • SCATTER3D - 3D scatter plots

These provide the same underlying functionality but with explicit names.