Linked context into things, adapted examples.

src/context.rs

@@ -1,5 +1,3 @@
-use parking_lot::ReentrantMutex;
-
 // TODO(4bb4) Do this properly.
 // I already added a simple Context struct that can be created once and used as long as it is not
 // dropped here for initial tests - this is of course neither threadsafe nor otherwise safe to use
@@ -22,6 +20,9 @@ use parking_lot::ReentrantMutex;
 //   I think I'll call this PlotUi to mimmick imgui-rs' Ui.
 // - Think about what this means in terms of the stacks and things like is_plot_hovered() -
 //   they should also only work when there is a context available.
+use parking_lot::ReentrantMutex;
+
+use crate::PlotUi;
 
 /// An implot context.
 ///
@@ -32,8 +33,7 @@ pub struct Context {
 }
 
 lazy_static! {
-    // This mutex needs to be used to guard all public functions that can affect the underlying
-    // ImPlot active context
+    // This mutex is used to guard any accesses to the context
     static ref CTX_MUTEX: ReentrantMutex<()> = ReentrantMutex::new(());
 }
 
@@ -57,6 +57,11 @@ impl Context {
         }
         Self { raw: ctx }
     }
+
+    /// Get a "plot ui" struct, this will be used to build actual plots.
+    pub fn get_plot_ui(&self) -> PlotUi {
+        PlotUi { context: self }
+    }
 }
 
 impl Drop for Context {

src/lib.rs

@@ -12,23 +12,25 @@ pub extern crate implot_sys as sys;
 #[macro_use]
 extern crate lazy_static;
 
-pub use sys::imgui::Condition;
-// TODO(4bb4) facade-wrap these
-pub use sys::{ImPlotLimits, ImPlotPoint, ImPlotRange, ImVec2, ImVec4};
+// TODO(4bb4) facade-wrap these?
+pub use sys::{imgui::Condition, ImPlotLimits, ImPlotPoint, ImPlotRange, ImVec2, ImVec4};
 
-// Plot struct and associated enums
-pub mod context;
-pub mod plot;
-pub mod plot_elements;
+pub use self::context::*;
+pub use self::plot::*;
+pub use self::plot_elements::*;
 
-pub use context::Context;
-pub use plot::{AxisFlags, Plot, PlotFlags};
-pub use plot_elements::{PlotBars, PlotLine, PlotScatter, PlotText};
+mod context;
+mod plot;
+mod plot_elements;
 
-// --- Enum definitions --------------------------------------------------------------------------
-// Things that are to be combined like flags are done using bitflags, and things that are meant
-// as enumerations in the traditional sense are plain enums.
+/// A temporary reference for building plots. This does not really do anything on its own at
+/// this point, but it is used to enforce that a context is created and active for other features,
+/// such as creating plots.
+pub struct PlotUi<'ui> {
+    context: &'ui Context,
+}
 
+// --- Markers, color maps, style variables----------------------------------------------------
 /// Markers, documentation copied from implot.h for convenience.
 #[repr(i32)]
 #[derive(Copy, Clone, Debug)]
@@ -190,11 +192,6 @@ pub enum StyleVar {
     PlotMinSize = sys::ImPlotStyleVar__ImPlotStyleVar_PlotMinSize,
 }
 
-// --- Context -----------------------------------------------------------------------------------
-
-// --- Main plot structure -----------------------------------------------------------------------
-
-// --- Color maps -----------------------------------------------------------------------------
 /// Switch to one of the built-in preset colormaps. If samples is greater than 1, the map will be
 /// linearly resampled.
 pub fn set_colormap_from_preset(preset: Colormap, samples: u32) {

src/plot.rs

@@ -8,6 +8,8 @@ pub use sys::imgui::Condition;
 use sys::imgui::{im_str, ImString};
 pub use sys::{ImPlotLimits, ImPlotPoint, ImPlotRange, ImVec2, ImVec4};
 
+use crate::{Context, PlotUi};
+
 const DEFAULT_PLOT_SIZE_X: f32 = 400.0;
 const DEFAULT_PLOT_SIZE_Y: f32 = 400.0;
 
@@ -375,7 +377,7 @@ impl Plot {
     ///
     /// For a convenient implementation of all this, use [`build()`](struct.Plot.html#method.build)
     /// instead.
-    pub fn begin(&self) -> Option<PlotToken> {
+    pub fn begin(&self, plot_ui: &PlotUi) -> Option<PlotToken> {
         self.maybe_set_axis_limits();
         self.maybe_set_tick_labels();
 
@@ -398,8 +400,8 @@ impl Plot {
 
         if should_render {
             Some(PlotToken {
+                context: plot_ui.context,
                 plot_title: self.title.clone(),
-                has_ended: false,
             })
         } else {
             // In contrast with imgui windows, end() does not have to be
@@ -412,8 +414,8 @@ impl Plot {
     ///
     /// Note: the closure is not called if ImPlot::BeginPlot() returned
     /// false - TODO(4bb4) figure out if this is if things are not rendered
-    pub fn build<F: FnOnce()>(self, f: F) {
-        if let Some(token) = self.begin() {
+    pub fn build<F: FnOnce()>(self, plot_ui: &PlotUi, f: F) {
+        if let Some(token) = self.begin(plot_ui) {
             f();
             token.end()
         }
@@ -422,23 +424,22 @@ impl Plot {
 
 /// Tracks a plot that must be ended by calling `.end()`
 pub struct PlotToken {
+    context: *const Context,
     /// For better error messages
     plot_title: String,
-    /// Whether end() has been called on this already or not
-    has_ended: bool,
 }
 
 impl PlotToken {
     /// End a previously begin()'ed plot.
     pub fn end(mut self) {
-        self.has_ended = true;
+        self.context = std::ptr::null();
         unsafe { sys::ImPlot_EndPlot() };
     }
 }
 
 impl Drop for PlotToken {
     fn drop(&mut self) {
-        if !self.has_ended && !std::thread::panicking() {
+        if !self.context.is_null() && !std::thread::panicking() {
             panic!(
                 "Warning: A PlotToken for plot \"{}\" was not called end() on",
                 self.plot_title