| 1 | //! 2D plotting engine |
| 2 | //! |
| 3 | //! Provides function plotting with: |
| 4 | //! - Explicit functions: y = f(x) |
| 5 | //! - Parametric curves: (x(t), y(t)) |
| 6 | //! - Coordinate system with axes and grid |
| 7 | //! - Pan/zoom interaction |
| 8 | //! - Trace mode |
| 9 | |
| 10 | use cairo::Context; |
| 11 | use garcalc_cas::{Evaluator, Expr, Symbol}; |
| 12 | |
| 13 | use crate::{Color, LineStyle, Plottable, Viewport2D}; |
| 14 | |
| 15 | /// Configuration for the plot appearance |
| 16 | #[derive(Debug, Clone)] |
| 17 | pub struct PlotConfig { |
| 18 | /// Background color |
| 19 | pub background: Color, |
| 20 | /// Axis color |
| 21 | pub axis_color: Color, |
| 22 | /// Grid color |
| 23 | pub grid_color: Color, |
| 24 | /// Tick label color |
| 25 | pub label_color: Color, |
| 26 | /// Whether to show grid |
| 27 | pub show_grid: bool, |
| 28 | /// Whether to show axis labels |
| 29 | pub show_labels: bool, |
| 30 | /// Line width for curves |
| 31 | pub curve_width: f64, |
| 32 | /// Line width for axes |
| 33 | pub axis_width: f64, |
| 34 | /// Line width for grid |
| 35 | pub grid_width: f64, |
| 36 | /// Number of samples per pixel for function plotting |
| 37 | pub samples_per_pixel: f64, |
| 38 | } |
| 39 | |
| 40 | impl Default for PlotConfig { |
| 41 | fn default() -> Self { |
| 42 | Self { |
| 43 | background: Color { |
| 44 | r: 30, |
| 45 | g: 30, |
| 46 | b: 46, |
| 47 | a: 255, |
| 48 | }, |
| 49 | axis_color: Color { |
| 50 | r: 166, |
| 51 | g: 173, |
| 52 | b: 200, |
| 53 | a: 255, |
| 54 | }, |
| 55 | grid_color: Color { |
| 56 | r: 69, |
| 57 | g: 71, |
| 58 | b: 90, |
| 59 | a: 255, |
| 60 | }, |
| 61 | label_color: Color { |
| 62 | r: 166, |
| 63 | g: 173, |
| 64 | b: 200, |
| 65 | a: 255, |
| 66 | }, |
| 67 | show_grid: true, |
| 68 | show_labels: true, |
| 69 | curve_width: 2.0, |
| 70 | axis_width: 1.5, |
| 71 | grid_width: 0.5, |
| 72 | samples_per_pixel: 2.0, |
| 73 | } |
| 74 | } |
| 75 | } |
| 76 | |
| 77 | /// Default curve colors (catppuccin palette) |
| 78 | pub const CURVE_COLORS: [Color; 6] = [ |
| 79 | Color { |
| 80 | r: 137, |
| 81 | g: 180, |
| 82 | b: 250, |
| 83 | a: 255, |
| 84 | }, // blue |
| 85 | Color { |
| 86 | r: 166, |
| 87 | g: 227, |
| 88 | b: 161, |
| 89 | a: 255, |
| 90 | }, // green |
| 91 | Color { |
| 92 | r: 249, |
| 93 | g: 226, |
| 94 | b: 175, |
| 95 | a: 255, |
| 96 | }, // yellow |
| 97 | Color { |
| 98 | r: 243, |
| 99 | g: 139, |
| 100 | b: 168, |
| 101 | a: 255, |
| 102 | }, // red |
| 103 | Color { |
| 104 | r: 203, |
| 105 | g: 166, |
| 106 | b: 247, |
| 107 | a: 255, |
| 108 | }, // mauve |
| 109 | Color { |
| 110 | r: 148, |
| 111 | g: 226, |
| 112 | b: 213, |
| 113 | a: 255, |
| 114 | }, // teal |
| 115 | ]; |
| 116 | |
| 117 | /// Viewport preset configurations |
| 118 | #[derive(Debug, Clone, Copy, PartialEq, Eq)] |
| 119 | pub enum ViewportPreset { |
| 120 | Standard, |
| 121 | Trig, |
| 122 | ZoomFit, |
| 123 | } |
| 124 | |
| 125 | /// A plotted function with visibility and label |
| 126 | #[derive(Debug, Clone)] |
| 127 | pub struct PlottedFunction { |
| 128 | pub func: Plottable, |
| 129 | pub visible: bool, |
| 130 | pub label: String, |
| 131 | } |
| 132 | |
| 133 | /// 2D graph state and renderer |
| 134 | pub struct Graph2D { |
| 135 | /// Current viewport |
| 136 | pub viewport: Viewport2D, |
| 137 | /// Plot configuration |
| 138 | pub config: PlotConfig, |
| 139 | /// Functions to plot |
| 140 | pub functions: Vec<PlottedFunction>, |
| 141 | /// Trace mode: show cursor position |
| 142 | pub trace_enabled: bool, |
| 143 | /// Current trace position (screen coords) |
| 144 | pub trace_pos: Option<(f64, f64)>, |
| 145 | } |
| 146 | |
| 147 | impl Default for Graph2D { |
| 148 | fn default() -> Self { |
| 149 | Self { |
| 150 | viewport: Viewport2D::default(), |
| 151 | config: PlotConfig::default(), |
| 152 | functions: Vec::new(), |
| 153 | trace_enabled: false, |
| 154 | trace_pos: None, |
| 155 | } |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | impl Graph2D { |
| 160 | /// Create a new graph with default settings |
| 161 | pub fn new() -> Self { |
| 162 | Self::default() |
| 163 | } |
| 164 | |
| 165 | /// Set the viewport |
| 166 | pub fn set_viewport(&mut self, viewport: Viewport2D) { |
| 167 | self.viewport = viewport; |
| 168 | } |
| 169 | |
| 170 | /// Add a function to plot |
| 171 | pub fn add_function(&mut self, func: Plottable, label: String) { |
| 172 | self.functions.push(PlottedFunction { |
| 173 | func, |
| 174 | visible: true, |
| 175 | label, |
| 176 | }); |
| 177 | } |
| 178 | |
| 179 | /// Add an explicit function y = f(x) with auto color |
| 180 | pub fn add_explicit(&mut self, expr: Expr) { |
| 181 | let color = CURVE_COLORS[self.functions.len() % CURVE_COLORS.len()]; |
| 182 | let label = format!("y = {}", expr); |
| 183 | self.functions.push(PlottedFunction { |
| 184 | func: Plottable::Explicit2D { |
| 185 | expr, |
| 186 | x_var: "x".to_string(), |
| 187 | color, |
| 188 | style: LineStyle::Solid, |
| 189 | }, |
| 190 | visible: true, |
| 191 | label, |
| 192 | }); |
| 193 | } |
| 194 | |
| 195 | /// Add an implicit curve F(x,y) = 0 |
| 196 | pub fn add_implicit(&mut self, expr: Expr) { |
| 197 | let color = CURVE_COLORS[self.functions.len() % CURVE_COLORS.len()]; |
| 198 | let label = format!("{} = 0", expr); |
| 199 | self.functions.push(PlottedFunction { |
| 200 | func: Plottable::Implicit2D { |
| 201 | expr, |
| 202 | x_var: "x".to_string(), |
| 203 | y_var: "y".to_string(), |
| 204 | color, |
| 205 | }, |
| 206 | visible: true, |
| 207 | label, |
| 208 | }); |
| 209 | } |
| 210 | |
| 211 | /// Add a parametric curve (x(t), y(t)) |
| 212 | pub fn add_parametric(&mut self, x_expr: Expr, y_expr: Expr, t_range: (f64, f64)) { |
| 213 | let color = CURVE_COLORS[self.functions.len() % CURVE_COLORS.len()]; |
| 214 | let label = format!("({}, {})", x_expr, y_expr); |
| 215 | self.functions.push(PlottedFunction { |
| 216 | func: Plottable::Parametric2D { |
| 217 | x_expr, |
| 218 | y_expr, |
| 219 | t_var: "t".to_string(), |
| 220 | t_range, |
| 221 | color, |
| 222 | }, |
| 223 | visible: true, |
| 224 | label, |
| 225 | }); |
| 226 | } |
| 227 | |
| 228 | /// Add a polar curve r = f(theta) |
| 229 | pub fn add_polar(&mut self, expr: Expr, theta_range: (f64, f64)) { |
| 230 | let color = CURVE_COLORS[self.functions.len() % CURVE_COLORS.len()]; |
| 231 | let label = format!("r = {}", expr); |
| 232 | self.functions.push(PlottedFunction { |
| 233 | func: Plottable::Polar2D { |
| 234 | expr, |
| 235 | theta_var: "theta".to_string(), |
| 236 | theta_range, |
| 237 | color, |
| 238 | style: LineStyle::Solid, |
| 239 | }, |
| 240 | visible: true, |
| 241 | label, |
| 242 | }); |
| 243 | } |
| 244 | |
| 245 | /// Add a piecewise function |
| 246 | pub fn add_piecewise(&mut self, pieces: Vec<crate::PiecewisePiece>) { |
| 247 | let color = CURVE_COLORS[self.functions.len() % CURVE_COLORS.len()]; |
| 248 | let label = format!("piecewise ({} pieces)", pieces.len()); |
| 249 | self.functions.push(PlottedFunction { |
| 250 | func: Plottable::Piecewise2D { |
| 251 | pieces, |
| 252 | x_var: "x".to_string(), |
| 253 | color, |
| 254 | style: LineStyle::Solid, |
| 255 | }, |
| 256 | visible: true, |
| 257 | label, |
| 258 | }); |
| 259 | } |
| 260 | |
| 261 | /// Apply a viewport preset |
| 262 | pub fn apply_viewport_preset(&mut self, preset: ViewportPreset) { |
| 263 | match preset { |
| 264 | ViewportPreset::Standard => { |
| 265 | self.viewport = Viewport2D::default(); |
| 266 | } |
| 267 | ViewportPreset::Trig => { |
| 268 | self.viewport = Viewport2D { |
| 269 | x_min: -2.0 * std::f64::consts::PI, |
| 270 | x_max: 2.0 * std::f64::consts::PI, |
| 271 | y_min: -1.5, |
| 272 | y_max: 1.5, |
| 273 | }; |
| 274 | } |
| 275 | ViewportPreset::ZoomFit => { |
| 276 | self.zoom_to_fit(); |
| 277 | } |
| 278 | } |
| 279 | } |
| 280 | |
| 281 | /// Auto-zoom to fit visible function outputs |
| 282 | pub fn zoom_to_fit(&mut self) { |
| 283 | let mut y_min = f64::INFINITY; |
| 284 | let mut y_max = f64::NEG_INFINITY; |
| 285 | let mut evaluator = Evaluator::new(); |
| 286 | let num_samples = 500; |
| 287 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 288 | let dx = x_range / num_samples as f64; |
| 289 | |
| 290 | for pf in &self.functions { |
| 291 | if !pf.visible { |
| 292 | continue; |
| 293 | } |
| 294 | if let Plottable::Explicit2D { ref expr, ref x_var, .. } = pf.func { |
| 295 | for i in 0..=num_samples { |
| 296 | let x = self.viewport.x_min + i as f64 * dx; |
| 297 | evaluator.set_var(x_var, Expr::Float(x)); |
| 298 | if let Ok(result) = evaluator.eval(expr) { |
| 299 | if let Ok(y) = expr_to_f64(&result) { |
| 300 | if y.is_finite() { |
| 301 | y_min = y_min.min(y); |
| 302 | y_max = y_max.max(y); |
| 303 | } |
| 304 | } |
| 305 | } |
| 306 | } |
| 307 | } |
| 308 | } |
| 309 | |
| 310 | if y_min.is_finite() && y_max.is_finite() && (y_max - y_min).abs() > 1e-10 { |
| 311 | let margin = (y_max - y_min) * 0.1; |
| 312 | self.viewport.y_min = y_min - margin; |
| 313 | self.viewport.y_max = y_max + margin; |
| 314 | } |
| 315 | } |
| 316 | |
| 317 | /// Set the color of a function at the given index |
| 318 | pub fn set_function_color(&mut self, index: usize, color: crate::Color) { |
| 319 | if let Some(pf) = self.functions.get_mut(index) { |
| 320 | pf.func.set_color(color); |
| 321 | } |
| 322 | } |
| 323 | |
| 324 | /// Toggle visibility of function at index |
| 325 | pub fn toggle_visibility(&mut self, index: usize) { |
| 326 | if let Some(f) = self.functions.get_mut(index) { |
| 327 | f.visible = !f.visible; |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | /// Clear all functions |
| 332 | pub fn clear_functions(&mut self) { |
| 333 | self.functions.clear(); |
| 334 | } |
| 335 | |
| 336 | /// Pan the viewport by a screen delta |
| 337 | pub fn pan(&mut self, dx: f64, dy: f64, width: u32, height: u32) { |
| 338 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 339 | let y_range = self.viewport.y_max - self.viewport.y_min; |
| 340 | |
| 341 | let math_dx = -dx * x_range / width as f64; |
| 342 | let math_dy = dy * y_range / height as f64; |
| 343 | |
| 344 | self.viewport.x_min += math_dx; |
| 345 | self.viewport.x_max += math_dx; |
| 346 | self.viewport.y_min += math_dy; |
| 347 | self.viewport.y_max += math_dy; |
| 348 | } |
| 349 | |
| 350 | /// Zoom by a factor centered at screen position |
| 351 | pub fn zoom(&mut self, factor: f64, cx: f64, cy: f64, width: u32, height: u32) { |
| 352 | // Convert screen position to math coordinates |
| 353 | let (mx, my) = self.screen_to_math(cx, cy, width, height); |
| 354 | |
| 355 | // Calculate new ranges |
| 356 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 357 | let y_range = self.viewport.y_max - self.viewport.y_min; |
| 358 | let new_x_range = x_range / factor; |
| 359 | let new_y_range = y_range / factor; |
| 360 | |
| 361 | // Calculate relative position of zoom center |
| 362 | let rx = (mx - self.viewport.x_min) / x_range; |
| 363 | let ry = (my - self.viewport.y_min) / y_range; |
| 364 | |
| 365 | // Set new viewport centered on zoom point |
| 366 | self.viewport.x_min = mx - rx * new_x_range; |
| 367 | self.viewport.x_max = mx + (1.0 - rx) * new_x_range; |
| 368 | self.viewport.y_min = my - ry * new_y_range; |
| 369 | self.viewport.y_max = my + (1.0 - ry) * new_y_range; |
| 370 | } |
| 371 | |
| 372 | /// Reset viewport to default |
| 373 | pub fn reset_viewport(&mut self) { |
| 374 | self.viewport = Viewport2D::default(); |
| 375 | } |
| 376 | |
| 377 | /// Convert screen coordinates to math coordinates |
| 378 | pub fn screen_to_math(&self, sx: f64, sy: f64, width: u32, height: u32) -> (f64, f64) { |
| 379 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 380 | let y_range = self.viewport.y_max - self.viewport.y_min; |
| 381 | |
| 382 | let mx = self.viewport.x_min + (sx / width as f64) * x_range; |
| 383 | let my = self.viewport.y_max - (sy / height as f64) * y_range; |
| 384 | |
| 385 | (mx, my) |
| 386 | } |
| 387 | |
| 388 | /// Convert math coordinates to screen coordinates |
| 389 | pub fn math_to_screen(&self, mx: f64, my: f64, width: u32, height: u32) -> (f64, f64) { |
| 390 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 391 | let y_range = self.viewport.y_max - self.viewport.y_min; |
| 392 | |
| 393 | let sx = ((mx - self.viewport.x_min) / x_range) * width as f64; |
| 394 | let sy = ((self.viewport.y_max - my) / y_range) * height as f64; |
| 395 | |
| 396 | (sx, sy) |
| 397 | } |
| 398 | |
| 399 | /// Update trace position |
| 400 | pub fn set_trace_pos(&mut self, x: f64, y: f64) { |
| 401 | self.trace_pos = Some((x, y)); |
| 402 | } |
| 403 | |
| 404 | /// Render the graph to a Cairo context |
| 405 | pub fn render(&self, ctx: &Context, width: u32, height: u32) { |
| 406 | let w = width as f64; |
| 407 | let h = height as f64; |
| 408 | |
| 409 | // Background |
| 410 | set_color(ctx, self.config.background); |
| 411 | ctx.rectangle(0.0, 0.0, w, h); |
| 412 | let _ = ctx.fill(); |
| 413 | |
| 414 | // Grid |
| 415 | if self.config.show_grid { |
| 416 | self.draw_grid(ctx, width, height); |
| 417 | } |
| 418 | |
| 419 | // Axes |
| 420 | self.draw_axes(ctx, width, height); |
| 421 | |
| 422 | // Functions |
| 423 | for pf in &self.functions { |
| 424 | if pf.visible { |
| 425 | self.draw_function(ctx, &pf.func, width, height); |
| 426 | } |
| 427 | } |
| 428 | |
| 429 | // Trace |
| 430 | if self.trace_enabled { |
| 431 | if let Some((sx, sy)) = self.trace_pos { |
| 432 | self.draw_trace(ctx, sx, sy, width, height); |
| 433 | } |
| 434 | } |
| 435 | } |
| 436 | |
| 437 | fn draw_grid(&self, ctx: &Context, width: u32, height: u32) { |
| 438 | set_color(ctx, self.config.grid_color); |
| 439 | ctx.set_line_width(self.config.grid_width); |
| 440 | |
| 441 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 442 | let y_range = self.viewport.y_max - self.viewport.y_min; |
| 443 | |
| 444 | // Calculate nice grid spacing |
| 445 | let x_step = nice_step(x_range / 10.0); |
| 446 | let y_step = nice_step(y_range / 10.0); |
| 447 | |
| 448 | // Vertical grid lines |
| 449 | let x_start = (self.viewport.x_min / x_step).floor() * x_step; |
| 450 | let mut x = x_start; |
| 451 | while x <= self.viewport.x_max { |
| 452 | let (sx, _) = self.math_to_screen(x, 0.0, width, height); |
| 453 | ctx.move_to(sx, 0.0); |
| 454 | ctx.line_to(sx, height as f64); |
| 455 | x += x_step; |
| 456 | } |
| 457 | |
| 458 | // Horizontal grid lines |
| 459 | let y_start = (self.viewport.y_min / y_step).floor() * y_step; |
| 460 | let mut y = y_start; |
| 461 | while y <= self.viewport.y_max { |
| 462 | let (_, sy) = self.math_to_screen(0.0, y, width, height); |
| 463 | ctx.move_to(0.0, sy); |
| 464 | ctx.line_to(width as f64, sy); |
| 465 | y += y_step; |
| 466 | } |
| 467 | |
| 468 | let _ = ctx.stroke(); |
| 469 | } |
| 470 | |
| 471 | fn draw_axes(&self, ctx: &Context, width: u32, height: u32) { |
| 472 | set_color(ctx, self.config.axis_color); |
| 473 | ctx.set_line_width(self.config.axis_width); |
| 474 | |
| 475 | // Y-axis (x = 0) |
| 476 | if self.viewport.x_min <= 0.0 && self.viewport.x_max >= 0.0 { |
| 477 | let (sx, _) = self.math_to_screen(0.0, 0.0, width, height); |
| 478 | ctx.move_to(sx, 0.0); |
| 479 | ctx.line_to(sx, height as f64); |
| 480 | } |
| 481 | |
| 482 | // X-axis (y = 0) |
| 483 | if self.viewport.y_min <= 0.0 && self.viewport.y_max >= 0.0 { |
| 484 | let (_, sy) = self.math_to_screen(0.0, 0.0, width, height); |
| 485 | ctx.move_to(0.0, sy); |
| 486 | ctx.line_to(width as f64, sy); |
| 487 | } |
| 488 | |
| 489 | let _ = ctx.stroke(); |
| 490 | |
| 491 | // Tick labels |
| 492 | if self.config.show_labels { |
| 493 | self.draw_tick_labels(ctx, width, height); |
| 494 | } |
| 495 | } |
| 496 | |
| 497 | fn draw_tick_labels(&self, ctx: &Context, width: u32, height: u32) { |
| 498 | set_color(ctx, self.config.label_color); |
| 499 | ctx.set_font_size(11.0); |
| 500 | |
| 501 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 502 | let y_range = self.viewport.y_max - self.viewport.y_min; |
| 503 | |
| 504 | let x_step = nice_step(x_range / 10.0); |
| 505 | let y_step = nice_step(y_range / 10.0); |
| 506 | |
| 507 | // Get y-axis position for x labels |
| 508 | let (_, y_axis_sy) = self.math_to_screen(0.0, 0.0, width, height); |
| 509 | let label_y = y_axis_sy.clamp(12.0, height as f64 - 4.0); |
| 510 | |
| 511 | // X-axis labels |
| 512 | let x_start = (self.viewport.x_min / x_step).ceil() * x_step; |
| 513 | let mut x = x_start; |
| 514 | while x <= self.viewport.x_max { |
| 515 | if x.abs() > x_step * 0.1 { |
| 516 | let (sx, _) = self.math_to_screen(x, 0.0, width, height); |
| 517 | let label = format_number(x); |
| 518 | ctx.move_to(sx - 10.0, label_y + 12.0); |
| 519 | let _ = ctx.show_text(&label); |
| 520 | } |
| 521 | x += x_step; |
| 522 | } |
| 523 | |
| 524 | // Get x-axis position for y labels |
| 525 | let (x_axis_sx, _) = self.math_to_screen(0.0, 0.0, width, height); |
| 526 | let label_x = x_axis_sx.clamp(4.0, width as f64 - 40.0); |
| 527 | |
| 528 | // Y-axis labels |
| 529 | let y_start = (self.viewport.y_min / y_step).ceil() * y_step; |
| 530 | let mut y = y_start; |
| 531 | while y <= self.viewport.y_max { |
| 532 | if y.abs() > y_step * 0.1 { |
| 533 | let (_, sy) = self.math_to_screen(0.0, y, width, height); |
| 534 | let label = format_number(y); |
| 535 | ctx.move_to(label_x + 4.0, sy + 4.0); |
| 536 | let _ = ctx.show_text(&label); |
| 537 | } |
| 538 | y += y_step; |
| 539 | } |
| 540 | } |
| 541 | |
| 542 | fn draw_function(&self, ctx: &Context, func: &Plottable, width: u32, height: u32) { |
| 543 | match func { |
| 544 | Plottable::Explicit2D { |
| 545 | expr, |
| 546 | x_var, |
| 547 | color, |
| 548 | style, |
| 549 | } => { |
| 550 | self.draw_explicit(ctx, expr, x_var, *color, *style, width, height); |
| 551 | } |
| 552 | Plottable::Implicit2D { |
| 553 | expr, |
| 554 | x_var, |
| 555 | y_var, |
| 556 | color, |
| 557 | } => { |
| 558 | self.draw_implicit(ctx, expr, x_var, y_var, *color, width, height); |
| 559 | } |
| 560 | Plottable::Parametric2D { |
| 561 | x_expr, |
| 562 | y_expr, |
| 563 | t_var, |
| 564 | t_range, |
| 565 | color, |
| 566 | } => { |
| 567 | self.draw_parametric(ctx, x_expr, y_expr, t_var, *t_range, *color, width, height); |
| 568 | } |
| 569 | Plottable::Polar2D { |
| 570 | expr, |
| 571 | theta_var, |
| 572 | theta_range, |
| 573 | color, |
| 574 | style, |
| 575 | } => { |
| 576 | self.draw_polar(ctx, expr, theta_var, *theta_range, *color, *style, width, height); |
| 577 | } |
| 578 | Plottable::Piecewise2D { |
| 579 | pieces, |
| 580 | x_var, |
| 581 | color, |
| 582 | style, |
| 583 | } => { |
| 584 | self.draw_piecewise(ctx, pieces, x_var, *color, *style, width, height); |
| 585 | } |
| 586 | _ => {} |
| 587 | } |
| 588 | } |
| 589 | |
| 590 | fn draw_explicit( |
| 591 | &self, |
| 592 | ctx: &Context, |
| 593 | expr: &Expr, |
| 594 | x_var: &str, |
| 595 | color: Color, |
| 596 | style: LineStyle, |
| 597 | width: u32, |
| 598 | height: u32, |
| 599 | ) { |
| 600 | set_color(ctx, color); |
| 601 | ctx.set_line_width(self.config.curve_width); |
| 602 | |
| 603 | match style { |
| 604 | LineStyle::Solid => ctx.set_dash(&[], 0.0), |
| 605 | LineStyle::Dashed => ctx.set_dash(&[6.0, 4.0], 0.0), |
| 606 | LineStyle::Dotted => ctx.set_dash(&[2.0, 2.0], 0.0), |
| 607 | } |
| 608 | |
| 609 | let mut evaluator = Evaluator::new(); |
| 610 | let _var = Symbol::from(x_var); |
| 611 | |
| 612 | // Sample the function |
| 613 | let num_samples = (width as f64 * self.config.samples_per_pixel) as usize; |
| 614 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 615 | let dx = x_range / num_samples as f64; |
| 616 | |
| 617 | let mut first = true; |
| 618 | let mut last_valid = false; |
| 619 | |
| 620 | for i in 0..=num_samples { |
| 621 | let math_x = self.viewport.x_min + i as f64 * dx; |
| 622 | evaluator.set_var(x_var, Expr::Float(math_x)); |
| 623 | |
| 624 | if let Ok(result) = evaluator.eval(expr) { |
| 625 | if let Ok(math_y) = expr_to_f64(&result) { |
| 626 | if math_y.is_finite() |
| 627 | && math_y >= self.viewport.y_min - x_range |
| 628 | && math_y <= self.viewport.y_max + x_range |
| 629 | { |
| 630 | let (sx, sy) = self.math_to_screen(math_x, math_y, width, height); |
| 631 | |
| 632 | if first || !last_valid { |
| 633 | ctx.move_to(sx, sy); |
| 634 | first = false; |
| 635 | } else { |
| 636 | ctx.line_to(sx, sy); |
| 637 | } |
| 638 | last_valid = true; |
| 639 | continue; |
| 640 | } |
| 641 | } |
| 642 | } |
| 643 | // Invalid point - break the line |
| 644 | if last_valid { |
| 645 | let _ = ctx.stroke(); |
| 646 | } |
| 647 | last_valid = false; |
| 648 | } |
| 649 | |
| 650 | let _ = ctx.stroke(); |
| 651 | ctx.set_dash(&[], 0.0); |
| 652 | } |
| 653 | |
| 654 | fn draw_parametric( |
| 655 | &self, |
| 656 | ctx: &Context, |
| 657 | x_expr: &Expr, |
| 658 | y_expr: &Expr, |
| 659 | t_var: &str, |
| 660 | t_range: (f64, f64), |
| 661 | color: Color, |
| 662 | width: u32, |
| 663 | height: u32, |
| 664 | ) { |
| 665 | set_color(ctx, color); |
| 666 | ctx.set_line_width(self.config.curve_width); |
| 667 | |
| 668 | let mut evaluator = Evaluator::new(); |
| 669 | |
| 670 | let num_samples = (width as f64 * self.config.samples_per_pixel) as usize; |
| 671 | let t_span = t_range.1 - t_range.0; |
| 672 | let dt = t_span / num_samples as f64; |
| 673 | |
| 674 | let mut first = true; |
| 675 | |
| 676 | for i in 0..=num_samples { |
| 677 | let t = t_range.0 + i as f64 * dt; |
| 678 | evaluator.set_var(t_var, Expr::Float(t)); |
| 679 | |
| 680 | let x_result = evaluator.eval(x_expr); |
| 681 | let y_result = evaluator.eval(y_expr); |
| 682 | |
| 683 | if let (Ok(x_val), Ok(y_val)) = (x_result, y_result) { |
| 684 | if let (Ok(math_x), Ok(math_y)) = (expr_to_f64(&x_val), expr_to_f64(&y_val)) { |
| 685 | if math_x.is_finite() && math_y.is_finite() { |
| 686 | let (sx, sy) = self.math_to_screen(math_x, math_y, width, height); |
| 687 | |
| 688 | if first { |
| 689 | ctx.move_to(sx, sy); |
| 690 | first = false; |
| 691 | } else { |
| 692 | ctx.line_to(sx, sy); |
| 693 | } |
| 694 | } |
| 695 | } |
| 696 | } |
| 697 | } |
| 698 | |
| 699 | let _ = ctx.stroke(); |
| 700 | } |
| 701 | |
| 702 | /// Draw implicit curve F(x,y) = 0 using marching squares |
| 703 | fn draw_implicit( |
| 704 | &self, |
| 705 | ctx: &Context, |
| 706 | expr: &Expr, |
| 707 | x_var: &str, |
| 708 | y_var: &str, |
| 709 | color: Color, |
| 710 | width: u32, |
| 711 | height: u32, |
| 712 | ) { |
| 713 | set_color(ctx, color); |
| 714 | ctx.set_line_width(self.config.curve_width); |
| 715 | |
| 716 | let mut evaluator = Evaluator::new(); |
| 717 | |
| 718 | // Grid resolution for marching squares |
| 719 | let grid_size = 100; // Number of cells per dimension |
| 720 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 721 | let y_range = self.viewport.y_max - self.viewport.y_min; |
| 722 | let dx = x_range / grid_size as f64; |
| 723 | let dy = y_range / grid_size as f64; |
| 724 | |
| 725 | // Evaluate F(x,y) at grid points |
| 726 | let mut values = vec![vec![0.0f64; grid_size + 1]; grid_size + 1]; |
| 727 | for i in 0..=grid_size { |
| 728 | let x = self.viewport.x_min + i as f64 * dx; |
| 729 | for j in 0..=grid_size { |
| 730 | let y = self.viewport.y_min + j as f64 * dy; |
| 731 | evaluator.set_var(x_var, Expr::Float(x)); |
| 732 | evaluator.set_var(y_var, Expr::Float(y)); |
| 733 | if let Ok(result) = evaluator.eval(expr) { |
| 734 | if let Ok(v) = expr_to_f64(&result) { |
| 735 | values[i][j] = if v.is_finite() { v } else { f64::NAN }; |
| 736 | } else { |
| 737 | values[i][j] = f64::NAN; |
| 738 | } |
| 739 | } else { |
| 740 | values[i][j] = f64::NAN; |
| 741 | } |
| 742 | } |
| 743 | } |
| 744 | |
| 745 | // Marching squares: for each cell, draw line segments where F=0 |
| 746 | for i in 0..grid_size { |
| 747 | for j in 0..grid_size { |
| 748 | let x0 = self.viewport.x_min + i as f64 * dx; |
| 749 | let y0 = self.viewport.y_min + j as f64 * dy; |
| 750 | let x1 = x0 + dx; |
| 751 | let y1 = y0 + dy; |
| 752 | |
| 753 | let v00 = values[i][j]; |
| 754 | let v10 = values[i + 1][j]; |
| 755 | let v01 = values[i][j + 1]; |
| 756 | let v11 = values[i + 1][j + 1]; |
| 757 | |
| 758 | // Skip cells with NaN |
| 759 | if v00.is_nan() || v10.is_nan() || v01.is_nan() || v11.is_nan() { |
| 760 | continue; |
| 761 | } |
| 762 | |
| 763 | // Classify cell corners by sign |
| 764 | let s00 = v00 >= 0.0; |
| 765 | let s10 = v10 >= 0.0; |
| 766 | let s01 = v01 >= 0.0; |
| 767 | let s11 = v11 >= 0.0; |
| 768 | |
| 769 | // Build case index (4-bit) |
| 770 | let case = |
| 771 | (s00 as u8) | ((s10 as u8) << 1) | ((s01 as u8) << 2) | ((s11 as u8) << 3); |
| 772 | |
| 773 | // Linear interpolation to find zero crossing on an edge |
| 774 | let interp = |va: f64, vb: f64| -> f64 { |
| 775 | if (va - vb).abs() < 1e-15 { |
| 776 | 0.5 |
| 777 | } else { |
| 778 | va / (va - vb) |
| 779 | } |
| 780 | }; |
| 781 | |
| 782 | // Edge midpoints where contour crosses |
| 783 | let e_bottom = || { |
| 784 | let t = interp(v00, v10); |
| 785 | (x0 + t * dx, y0) |
| 786 | }; |
| 787 | let e_top = || { |
| 788 | let t = interp(v01, v11); |
| 789 | (x0 + t * dx, y1) |
| 790 | }; |
| 791 | let e_left = || { |
| 792 | let t = interp(v00, v01); |
| 793 | (x0, y0 + t * dy) |
| 794 | }; |
| 795 | let e_right = || { |
| 796 | let t = interp(v10, v11); |
| 797 | (x1, y0 + t * dy) |
| 798 | }; |
| 799 | |
| 800 | // Draw line segments based on marching squares case |
| 801 | let draw_line = |p1: (f64, f64), p2: (f64, f64)| { |
| 802 | let (sx1, sy1) = self.math_to_screen(p1.0, p1.1, width, height); |
| 803 | let (sx2, sy2) = self.math_to_screen(p2.0, p2.1, width, height); |
| 804 | ctx.move_to(sx1, sy1); |
| 805 | ctx.line_to(sx2, sy2); |
| 806 | }; |
| 807 | |
| 808 | match case { |
| 809 | 0 | 15 => {} // All same sign - no contour |
| 810 | 1 | 14 => draw_line(e_bottom(), e_left()), |
| 811 | 2 | 13 => draw_line(e_bottom(), e_right()), |
| 812 | 3 | 12 => draw_line(e_left(), e_right()), |
| 813 | 4 | 11 => draw_line(e_left(), e_top()), |
| 814 | 5 | 10 => { |
| 815 | // Ambiguous - saddle point. Draw both segments. |
| 816 | draw_line(e_bottom(), e_left()); |
| 817 | draw_line(e_top(), e_right()); |
| 818 | } |
| 819 | 6 | 9 => { |
| 820 | draw_line(e_bottom(), e_top()); |
| 821 | } |
| 822 | 7 | 8 => draw_line(e_top(), e_right()), |
| 823 | _ => {} |
| 824 | } |
| 825 | } |
| 826 | } |
| 827 | |
| 828 | let _ = ctx.stroke(); |
| 829 | } |
| 830 | |
| 831 | fn draw_polar( |
| 832 | &self, |
| 833 | ctx: &Context, |
| 834 | expr: &Expr, |
| 835 | theta_var: &str, |
| 836 | theta_range: (f64, f64), |
| 837 | color: Color, |
| 838 | style: LineStyle, |
| 839 | width: u32, |
| 840 | height: u32, |
| 841 | ) { |
| 842 | set_color(ctx, color); |
| 843 | ctx.set_line_width(self.config.curve_width); |
| 844 | match style { |
| 845 | LineStyle::Solid => ctx.set_dash(&[], 0.0), |
| 846 | LineStyle::Dashed => ctx.set_dash(&[6.0, 4.0], 0.0), |
| 847 | LineStyle::Dotted => ctx.set_dash(&[2.0, 2.0], 0.0), |
| 848 | } |
| 849 | |
| 850 | let mut evaluator = Evaluator::new(); |
| 851 | let num_samples = (width as f64 * self.config.samples_per_pixel) as usize; |
| 852 | let theta_span = theta_range.1 - theta_range.0; |
| 853 | let dtheta = theta_span / num_samples as f64; |
| 854 | let mut first = true; |
| 855 | |
| 856 | for i in 0..=num_samples { |
| 857 | let theta = theta_range.0 + i as f64 * dtheta; |
| 858 | evaluator.set_var(theta_var, Expr::Float(theta)); |
| 859 | if let Ok(result) = evaluator.eval(expr) { |
| 860 | if let Ok(r) = expr_to_f64(&result) { |
| 861 | if r.is_finite() { |
| 862 | let math_x = r * theta.cos(); |
| 863 | let math_y = r * theta.sin(); |
| 864 | let (sx, sy) = self.math_to_screen(math_x, math_y, width, height); |
| 865 | if first { |
| 866 | ctx.move_to(sx, sy); |
| 867 | first = false; |
| 868 | } else { |
| 869 | ctx.line_to(sx, sy); |
| 870 | } |
| 871 | continue; |
| 872 | } |
| 873 | } |
| 874 | } |
| 875 | if !first { |
| 876 | let _ = ctx.stroke(); |
| 877 | first = true; |
| 878 | } |
| 879 | } |
| 880 | let _ = ctx.stroke(); |
| 881 | ctx.set_dash(&[], 0.0); |
| 882 | } |
| 883 | |
| 884 | fn draw_piecewise( |
| 885 | &self, |
| 886 | ctx: &Context, |
| 887 | pieces: &[crate::PiecewisePiece], |
| 888 | x_var: &str, |
| 889 | color: Color, |
| 890 | style: LineStyle, |
| 891 | width: u32, |
| 892 | height: u32, |
| 893 | ) { |
| 894 | set_color(ctx, color); |
| 895 | ctx.set_line_width(self.config.curve_width); |
| 896 | match style { |
| 897 | LineStyle::Solid => ctx.set_dash(&[], 0.0), |
| 898 | LineStyle::Dashed => ctx.set_dash(&[6.0, 4.0], 0.0), |
| 899 | LineStyle::Dotted => ctx.set_dash(&[2.0, 2.0], 0.0), |
| 900 | } |
| 901 | |
| 902 | let mut evaluator = Evaluator::new(); |
| 903 | let num_samples = (width as f64 * self.config.samples_per_pixel) as usize; |
| 904 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 905 | let dx = x_range / num_samples as f64; |
| 906 | let mut first = true; |
| 907 | let mut last_valid = false; |
| 908 | let mut last_piece_idx: Option<usize> = None; |
| 909 | |
| 910 | for i in 0..=num_samples { |
| 911 | let math_x = self.viewport.x_min + i as f64 * dx; |
| 912 | let piece_idx = pieces.iter().position(|p| p.condition.matches(math_x)); |
| 913 | |
| 914 | if piece_idx != last_piece_idx && last_valid { |
| 915 | let _ = ctx.stroke(); |
| 916 | first = true; |
| 917 | last_valid = false; |
| 918 | } |
| 919 | last_piece_idx = piece_idx; |
| 920 | |
| 921 | if let Some(idx) = piece_idx { |
| 922 | evaluator.set_var(x_var, Expr::Float(math_x)); |
| 923 | if let Ok(result) = evaluator.eval(&pieces[idx].expr) { |
| 924 | if let Ok(math_y) = expr_to_f64(&result) { |
| 925 | if math_y.is_finite() |
| 926 | && math_y >= self.viewport.y_min - x_range |
| 927 | && math_y <= self.viewport.y_max + x_range |
| 928 | { |
| 929 | let (sx, sy) = self.math_to_screen(math_x, math_y, width, height); |
| 930 | if first || !last_valid { |
| 931 | ctx.move_to(sx, sy); |
| 932 | first = false; |
| 933 | } else { |
| 934 | ctx.line_to(sx, sy); |
| 935 | } |
| 936 | last_valid = true; |
| 937 | continue; |
| 938 | } |
| 939 | } |
| 940 | } |
| 941 | } |
| 942 | if last_valid { |
| 943 | let _ = ctx.stroke(); |
| 944 | } |
| 945 | last_valid = false; |
| 946 | } |
| 947 | let _ = ctx.stroke(); |
| 948 | ctx.set_dash(&[], 0.0); |
| 949 | } |
| 950 | |
| 951 | /// Find zeros (x-intercepts) of all visible Explicit2D functions |
| 952 | pub fn find_zeros(&self) -> Vec<(usize, Vec<(f64, f64)>)> { |
| 953 | let mut result = Vec::new(); |
| 954 | for (idx, pf) in self.functions.iter().enumerate() { |
| 955 | if !pf.visible { |
| 956 | continue; |
| 957 | } |
| 958 | if let Plottable::Explicit2D { ref expr, ref x_var, .. } = pf.func { |
| 959 | let zeros = self.find_zeros_for_expr(expr, x_var); |
| 960 | if !zeros.is_empty() { |
| 961 | result.push((idx, zeros)); |
| 962 | } |
| 963 | } |
| 964 | } |
| 965 | result |
| 966 | } |
| 967 | |
| 968 | fn find_zeros_for_expr(&self, expr: &Expr, x_var: &str) -> Vec<(f64, f64)> { |
| 969 | let mut evaluator = Evaluator::new(); |
| 970 | let mut zeros = Vec::new(); |
| 971 | let num_samples = 500; |
| 972 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 973 | let dx = x_range / num_samples as f64; |
| 974 | |
| 975 | let eval_at = |eval: &mut Evaluator, x: f64| -> Option<f64> { |
| 976 | eval.set_var(x_var, Expr::Float(x)); |
| 977 | eval.eval(expr) |
| 978 | .ok() |
| 979 | .and_then(|r| expr_to_f64(&r).ok()) |
| 980 | .filter(|y| y.is_finite()) |
| 981 | }; |
| 982 | |
| 983 | let mut prev: Option<f64> = None; |
| 984 | let mut prev_x = self.viewport.x_min; |
| 985 | |
| 986 | for i in 0..=num_samples { |
| 987 | let x = self.viewport.x_min + i as f64 * dx; |
| 988 | if let Some(y) = eval_at(&mut evaluator, x) { |
| 989 | if let Some(py) = prev { |
| 990 | if py * y < 0.0 { |
| 991 | if let Some(zx) = self.bisect(expr, x_var, prev_x, x, 50) { |
| 992 | if zeros |
| 993 | .last() |
| 994 | .map_or(true, |&(lx, _): &(f64, f64)| (lx - zx).abs() > dx * 0.1) |
| 995 | { |
| 996 | zeros.push((zx, 0.0)); |
| 997 | } |
| 998 | } |
| 999 | } |
| 1000 | } |
| 1001 | prev = Some(y); |
| 1002 | prev_x = x; |
| 1003 | } else { |
| 1004 | prev = None; |
| 1005 | } |
| 1006 | } |
| 1007 | zeros |
| 1008 | } |
| 1009 | |
| 1010 | fn bisect( |
| 1011 | &self, |
| 1012 | expr: &Expr, |
| 1013 | x_var: &str, |
| 1014 | mut a: f64, |
| 1015 | mut b: f64, |
| 1016 | max_iter: usize, |
| 1017 | ) -> Option<f64> { |
| 1018 | let mut evaluator = Evaluator::new(); |
| 1019 | let eval_at = |eval: &mut Evaluator, x: f64| -> Option<f64> { |
| 1020 | eval.set_var(x_var, Expr::Float(x)); |
| 1021 | eval.eval(expr) |
| 1022 | .ok() |
| 1023 | .and_then(|r| expr_to_f64(&r).ok()) |
| 1024 | .filter(|y| y.is_finite()) |
| 1025 | }; |
| 1026 | |
| 1027 | let fa = eval_at(&mut evaluator, a)?; |
| 1028 | if fa.abs() < 1e-12 { |
| 1029 | return Some(a); |
| 1030 | } |
| 1031 | |
| 1032 | for _ in 0..max_iter { |
| 1033 | let mid = (a + b) / 2.0; |
| 1034 | let fm = eval_at(&mut evaluator, mid)?; |
| 1035 | if fm.abs() < 1e-12 || (b - a).abs() < 1e-12 { |
| 1036 | return Some(mid); |
| 1037 | } |
| 1038 | if fa * fm < 0.0 { |
| 1039 | b = mid; |
| 1040 | } else { |
| 1041 | a = mid; |
| 1042 | } |
| 1043 | } |
| 1044 | Some((a + b) / 2.0) |
| 1045 | } |
| 1046 | |
| 1047 | /// Find intersections between pairs of visible Explicit2D functions |
| 1048 | pub fn find_intersections(&self) -> Vec<((usize, usize), Vec<(f64, f64)>)> { |
| 1049 | let mut result = Vec::new(); |
| 1050 | let explicit_indices: Vec<usize> = self |
| 1051 | .functions |
| 1052 | .iter() |
| 1053 | .enumerate() |
| 1054 | .filter(|(_, pf)| pf.visible && matches!(pf.func, Plottable::Explicit2D { .. })) |
| 1055 | .map(|(i, _)| i) |
| 1056 | .collect(); |
| 1057 | |
| 1058 | for i in 0..explicit_indices.len() { |
| 1059 | for j in (i + 1)..explicit_indices.len() { |
| 1060 | let idx_i = explicit_indices[i]; |
| 1061 | let idx_j = explicit_indices[j]; |
| 1062 | let points = self.find_intersection_points(idx_i, idx_j); |
| 1063 | if !points.is_empty() { |
| 1064 | result.push(((idx_i, idx_j), points)); |
| 1065 | } |
| 1066 | } |
| 1067 | } |
| 1068 | result |
| 1069 | } |
| 1070 | |
| 1071 | fn find_intersection_points(&self, idx_i: usize, idx_j: usize) -> Vec<(f64, f64)> { |
| 1072 | let (expr_i, var_i) = match &self.functions[idx_i].func { |
| 1073 | Plottable::Explicit2D { expr, x_var, .. } => (expr, x_var.as_str()), |
| 1074 | _ => return Vec::new(), |
| 1075 | }; |
| 1076 | let (expr_j, _) = match &self.functions[idx_j].func { |
| 1077 | Plottable::Explicit2D { expr, x_var, .. } => (expr, x_var.as_str()), |
| 1078 | _ => return Vec::new(), |
| 1079 | }; |
| 1080 | |
| 1081 | let mut eval_i = Evaluator::new(); |
| 1082 | let mut eval_j = Evaluator::new(); |
| 1083 | let mut points = Vec::new(); |
| 1084 | let num_samples = 500; |
| 1085 | let x_range = self.viewport.x_max - self.viewport.x_min; |
| 1086 | let dx = x_range / num_samples as f64; |
| 1087 | |
| 1088 | let eval_diff = |ei: &mut Evaluator, ej: &mut Evaluator, x: f64| -> Option<f64> { |
| 1089 | ei.set_var(var_i, Expr::Float(x)); |
| 1090 | ej.set_var(var_i, Expr::Float(x)); |
| 1091 | let yi = ei.eval(expr_i).ok().and_then(|r| expr_to_f64(&r).ok())?; |
| 1092 | let yj = ej.eval(expr_j).ok().and_then(|r| expr_to_f64(&r).ok())?; |
| 1093 | if yi.is_finite() && yj.is_finite() { |
| 1094 | Some(yi - yj) |
| 1095 | } else { |
| 1096 | None |
| 1097 | } |
| 1098 | }; |
| 1099 | |
| 1100 | let mut prev_diff: Option<f64> = None; |
| 1101 | let mut prev_x = self.viewport.x_min; |
| 1102 | |
| 1103 | for i in 0..=num_samples { |
| 1104 | let x = self.viewport.x_min + i as f64 * dx; |
| 1105 | if let Some(diff) = eval_diff(&mut eval_i, &mut eval_j, x) { |
| 1106 | if let Some(pd) = prev_diff { |
| 1107 | if pd * diff < 0.0 { |
| 1108 | let mut a = prev_x; |
| 1109 | let mut b = x; |
| 1110 | for _ in 0..50 { |
| 1111 | let mid = (a + b) / 2.0; |
| 1112 | if let Some(dm) = eval_diff(&mut eval_i, &mut eval_j, mid) { |
| 1113 | if dm.abs() < 1e-12 || (b - a).abs() < 1e-12 { |
| 1114 | a = mid; |
| 1115 | b = mid; |
| 1116 | break; |
| 1117 | } |
| 1118 | if pd * dm < 0.0 { |
| 1119 | b = mid; |
| 1120 | } else { |
| 1121 | a = mid; |
| 1122 | } |
| 1123 | } else { |
| 1124 | break; |
| 1125 | } |
| 1126 | } |
| 1127 | let zx = (a + b) / 2.0; |
| 1128 | eval_i.set_var(var_i, Expr::Float(zx)); |
| 1129 | if let Ok(r) = eval_i.eval(expr_i) { |
| 1130 | if let Ok(zy) = expr_to_f64(&r) { |
| 1131 | if zy.is_finite() |
| 1132 | && points.last().map_or(true, |&(lx, _): &(f64, f64)| { |
| 1133 | (lx - zx).abs() > dx * 0.1 |
| 1134 | }) |
| 1135 | { |
| 1136 | points.push((zx, zy)); |
| 1137 | } |
| 1138 | } |
| 1139 | } |
| 1140 | } |
| 1141 | } |
| 1142 | prev_diff = Some(diff); |
| 1143 | prev_x = x; |
| 1144 | } else { |
| 1145 | prev_diff = None; |
| 1146 | } |
| 1147 | } |
| 1148 | points |
| 1149 | } |
| 1150 | |
| 1151 | /// Draw marker circles at given points |
| 1152 | pub fn draw_markers( |
| 1153 | &self, |
| 1154 | ctx: &Context, |
| 1155 | points: &[(f64, f64)], |
| 1156 | color: Color, |
| 1157 | width: u32, |
| 1158 | height: u32, |
| 1159 | ) { |
| 1160 | set_color(ctx, color); |
| 1161 | for &(mx, my) in points { |
| 1162 | let (sx, sy) = self.math_to_screen(mx, my, width, height); |
| 1163 | ctx.arc(sx, sy, 4.0, 0.0, std::f64::consts::TAU); |
| 1164 | let _ = ctx.fill(); |
| 1165 | |
| 1166 | let label = format!("({:.3}, {:.3})", mx, my); |
| 1167 | ctx.set_font_size(10.0); |
| 1168 | ctx.move_to(sx + 6.0, sy - 6.0); |
| 1169 | let _ = ctx.show_text(&label); |
| 1170 | } |
| 1171 | } |
| 1172 | |
| 1173 | /// Generate a table of (x, f(x)) values for an Explicit2D function |
| 1174 | pub fn generate_table( |
| 1175 | &self, |
| 1176 | func_index: usize, |
| 1177 | x_min: f64, |
| 1178 | x_max: f64, |
| 1179 | step: f64, |
| 1180 | ) -> Vec<(f64, Option<f64>)> { |
| 1181 | let pf = match self.functions.get(func_index) { |
| 1182 | Some(f) => f, |
| 1183 | None => return Vec::new(), |
| 1184 | }; |
| 1185 | let (expr, x_var) = match &pf.func { |
| 1186 | Plottable::Explicit2D { expr, x_var, .. } => (expr, x_var.as_str()), |
| 1187 | _ => return Vec::new(), |
| 1188 | }; |
| 1189 | |
| 1190 | let mut evaluator = Evaluator::new(); |
| 1191 | let mut table = Vec::new(); |
| 1192 | let mut x = x_min; |
| 1193 | while x <= x_max + step * 0.01 { |
| 1194 | evaluator.set_var(x_var, Expr::Float(x)); |
| 1195 | let y = evaluator |
| 1196 | .eval(expr) |
| 1197 | .ok() |
| 1198 | .and_then(|r| expr_to_f64(&r).ok()) |
| 1199 | .filter(|v| v.is_finite()); |
| 1200 | table.push((x, y)); |
| 1201 | x += step; |
| 1202 | } |
| 1203 | table |
| 1204 | } |
| 1205 | |
| 1206 | fn draw_trace(&self, ctx: &Context, sx: f64, sy: f64, width: u32, height: u32) { |
| 1207 | let (mx, my) = self.screen_to_math(sx, sy, width, height); |
| 1208 | |
| 1209 | // Crosshair |
| 1210 | set_color(ctx, self.config.axis_color); |
| 1211 | ctx.set_line_width(0.5); |
| 1212 | ctx.set_dash(&[4.0, 4.0], 0.0); |
| 1213 | |
| 1214 | ctx.move_to(sx, 0.0); |
| 1215 | ctx.line_to(sx, height as f64); |
| 1216 | ctx.move_to(0.0, sy); |
| 1217 | ctx.line_to(width as f64, sy); |
| 1218 | let _ = ctx.stroke(); |
| 1219 | ctx.set_dash(&[], 0.0); |
| 1220 | |
| 1221 | // Coordinate display |
| 1222 | set_color( |
| 1223 | ctx, |
| 1224 | Color { |
| 1225 | r: 30, |
| 1226 | g: 30, |
| 1227 | b: 46, |
| 1228 | a: 200, |
| 1229 | }, |
| 1230 | ); |
| 1231 | let label = format!("({:.4}, {:.4})", mx, my); |
| 1232 | let label_w = label.len() as f64 * 7.0 + 8.0; |
| 1233 | let label_h = 18.0; |
| 1234 | let lx = (sx + 10.0).min(width as f64 - label_w - 4.0); |
| 1235 | let ly = (sy - 24.0).max(4.0); |
| 1236 | |
| 1237 | ctx.rectangle(lx, ly, label_w, label_h); |
| 1238 | let _ = ctx.fill(); |
| 1239 | |
| 1240 | set_color(ctx, self.config.label_color); |
| 1241 | ctx.set_font_size(12.0); |
| 1242 | ctx.move_to(lx + 4.0, ly + 13.0); |
| 1243 | let _ = ctx.show_text(&label); |
| 1244 | } |
| 1245 | } |
| 1246 | |
| 1247 | /// Set Cairo source color |
| 1248 | fn set_color(ctx: &Context, color: Color) { |
| 1249 | ctx.set_source_rgba( |
| 1250 | color.r as f64 / 255.0, |
| 1251 | color.g as f64 / 255.0, |
| 1252 | color.b as f64 / 255.0, |
| 1253 | color.a as f64 / 255.0, |
| 1254 | ); |
| 1255 | } |
| 1256 | |
| 1257 | /// Calculate a nice step size for grid/ticks |
| 1258 | fn nice_step(rough: f64) -> f64 { |
| 1259 | let exp = rough.abs().log10().floor(); |
| 1260 | let frac = rough / 10f64.powf(exp); |
| 1261 | |
| 1262 | let nice = if frac < 1.5 { |
| 1263 | 1.0 |
| 1264 | } else if frac <= 3.0 { |
| 1265 | 2.0 |
| 1266 | } else if frac < 7.0 { |
| 1267 | 5.0 |
| 1268 | } else { |
| 1269 | 10.0 |
| 1270 | }; |
| 1271 | |
| 1272 | nice * 10f64.powf(exp) |
| 1273 | } |
| 1274 | |
| 1275 | /// Format a number for axis labels |
| 1276 | fn format_number(x: f64) -> String { |
| 1277 | if x == 0.0 { |
| 1278 | return "0".to_string(); |
| 1279 | } |
| 1280 | let abs = x.abs(); |
| 1281 | if abs >= 1000.0 || abs < 0.01 { |
| 1282 | format!("{:.1e}", x) |
| 1283 | } else if abs >= 1.0 { |
| 1284 | format!("{:.1}", x) |
| 1285 | } else { |
| 1286 | format!("{:.2}", x) |
| 1287 | } |
| 1288 | } |
| 1289 | |
| 1290 | /// Convert an Expr to f64 |
| 1291 | fn expr_to_f64(expr: &Expr) -> Result<f64, ()> { |
| 1292 | match expr { |
| 1293 | Expr::Integer(n) => Ok(*n as f64), |
| 1294 | Expr::Float(x) => Ok(*x), |
| 1295 | Expr::Rational(r) => Ok(r.to_f64()), |
| 1296 | _ => Err(()), |
| 1297 | } |
| 1298 | } |
| 1299 | |
| 1300 | #[cfg(test)] |
| 1301 | mod tests { |
| 1302 | use super::*; |
| 1303 | |
| 1304 | #[test] |
| 1305 | fn test_coordinate_transform() { |
| 1306 | let graph = Graph2D::new(); |
| 1307 | let (mx, my) = graph.screen_to_math(250.0, 250.0, 500, 500); |
| 1308 | assert!((mx - 0.0).abs() < 0.01); |
| 1309 | assert!((my - 0.0).abs() < 0.01); |
| 1310 | } |
| 1311 | |
| 1312 | #[test] |
| 1313 | fn test_nice_step() { |
| 1314 | assert_eq!(nice_step(0.03), 0.02); |
| 1315 | assert_eq!(nice_step(0.3), 0.2); |
| 1316 | assert_eq!(nice_step(3.0), 2.0); |
| 1317 | assert_eq!(nice_step(30.0), 20.0); |
| 1318 | } |
| 1319 | } |
| 1320 |