dear-imgui-rs 0.17.0

High-level Rust bindings to Dear ImGui v1.92.9b with docking, WGPU/GL backends, and extensions (ImPlot/ImPlot3D, ImNodes, ImGuizmo, file browser, reflection-based UI)
Documentation 
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use std::marker::PhantomData;

use crate::sys;

use super::super::color::ImColor32;
use super::super::util::{assert_non_negative_f32, finite_vec2, finite_vec4};
use super::DrawListMut;

/// Private guard for the closure-only text pixel-snap scope.
struct TextNoPixelSnapGuard<'draw_list> {
    draw_list: *mut sys::ImDrawList,
    was_enabled: bool,
    _marker: PhantomData<&'draw_list sys::ImDrawList>,
}

impl Drop for TextNoPixelSnapGuard<'_> {
    fn drop(&mut self) {
        let flag = sys::ImDrawListFlags_TextNoPixelSnap as sys::ImDrawListFlags;
        unsafe {
            if self.was_enabled {
                (*self.draw_list).Flags |= flag;
            } else {
                (*self.draw_list).Flags &= !flag;
            }
        }
    }
}

impl<'ui> DrawListMut<'ui> {
    fn text_no_pixel_snap_guard(&self) -> TextNoPixelSnapGuard<'_> {
        let flag = sys::ImDrawListFlags_TextNoPixelSnap as sys::ImDrawListFlags;
        let was_enabled = unsafe { (*self.draw_list).Flags & flag != 0 };
        unsafe {
            (*self.draw_list).Flags |= flag;
        }
        TextNoPixelSnapGuard {
            draw_list: self.draw_list,
            was_enabled,
            _marker: PhantomData,
        }
    }

    /// Disables text pixel snapping while `f` runs and restores the prior state afterwards.
    ///
    /// Restoration also occurs if `f` panics. Changes to unrelated draw-list flags are preserved.
    pub fn with_text_no_pixel_snap<R>(&self, f: impl FnOnce() -> R) -> R {
        let text_flags = self.text_no_pixel_snap_guard();
        let result = f();
        drop(text_flags);
        result
    }

    /// Draw a text whose upper-left corner is at point `pos`.
    pub fn add_text(
        &self,
        pos: impl Into<sys::ImVec2>,
        col: impl Into<ImColor32>,
        text: impl AsRef<str>,
    ) {
        use std::os::raw::c_char;

        let text = text.as_ref();
        let pos = finite_vec2("DrawListMut::add_text()", "pos", pos);
        let col = col.into();

        unsafe {
            let start = text.as_ptr() as *const c_char;
            let end = (start as usize + text.len()) as *const c_char;
            sys::ImDrawList_AddText_Vec2(self.draw_list, pos, col.into(), start, end);
        }
    }

    /// Draw text with an explicit font and optional fine CPU clip rectangle.
    ///
    /// This mirrors Dear ImGui's `ImDrawList::AddText(ImFont*, ...)` overload.
    #[doc(alias = "AddText")]
    pub fn add_text_with_font(
        &self,
        font: crate::fonts::FontId,
        font_size: f32,
        pos: impl Into<sys::ImVec2>,
        col: impl Into<ImColor32>,
        text: impl AsRef<str>,
        wrap_width: f32,
        cpu_fine_clip_rect: Option<[f32; 4]>,
    ) {
        use std::os::raw::c_char;
        let text = text.as_ref();
        let pos = finite_vec2("DrawListMut::add_text_with_font()", "pos", pos);
        assert_non_negative_f32("DrawListMut::add_text_with_font()", "font_size", font_size);
        assert_non_negative_f32(
            "DrawListMut::add_text_with_font()",
            "wrap_width",
            wrap_width,
        );
        let col = col.into();
        let font_ptr = crate::fonts::validate_font_id_for_current_context(
            font,
            "DrawListMut::add_text_with_font()",
        );

        let clip_vec4 = cpu_fine_clip_rect
            .map(|r| finite_vec4("DrawListMut::add_text_with_font()", "cpu_fine_clip_rect", r));
        let clip_ptr = match clip_vec4.as_ref() {
            Some(v) => v as *const sys::ImVec4,
            None => std::ptr::null(),
        };

        unsafe {
            let start = text.as_ptr() as *const c_char;
            let end = (start as usize + text.len()) as *const c_char;
            sys::ImDrawList_AddText_FontPtr(
                self.draw_list,
                font_ptr,
                font_size,
                pos,
                col.into(),
                start,
                end,
                wrap_width,
                clip_ptr,
            );
        }
    }
}