feat: Configurable contrast and gamma (#2510)

* Configurable text contrast and gamma

* Explicitly specify the colorspace to use

* Change default hinting to slight

Full hinting is a bit too aggressive, especially with fractional font sizes

* Update the documentation

* Cargo fmt

* Set font hinting none as default

---------

Co-authored-by: Kaylee Simmons <[email protected]>

src/renderer/fonts/font_options.rs

@@ -298,10 +298,10 @@ impl FontEdging {
 
 #[derive(Clone, Debug, Hash, PartialEq, Eq, Default)]
 pub enum FontHinting {
- #[default]
  Full,
  Normal,
  Slight,
+ #[default]
  None,
 }
 

src/renderer/mod.rs

@@ -97,6 +97,8 @@ pub struct RendererSettings {
  debug_renderer: bool,
  profiler: bool,
  underline_stroke_scale: f32,
+ text_gamma: f32,
+ text_contrast: f32,
 }
 
 impl Default for RendererSettings {
@@ -115,6 +117,8 @@ impl Default for RendererSettings {
  debug_renderer: false,
  profiler: false,
  underline_stroke_scale: 1.,
+ text_gamma: 0.0,
+ text_contrast: 0.5,
  }
  }
 }

src/renderer/opengl.rs

@@ -23,7 +23,7 @@ use skia_safe::{
  backend_render_targets::make_gl, gl::FramebufferInfo, surfaces::wrap_backend_render_target,
  DirectContext, SurfaceOrigin,
  },
- ColorType,
+ ColorSpace, ColorType, PixelGeometry, SurfaceProps, SurfacePropsFlags,
 };
 use winit::{
  dpi::PhysicalSize,
@@ -37,9 +37,9 @@ pub use super::vsync::VSyncWinDwm;
 #[cfg(target_os = "macos")]
 pub use super::vsync::VSyncMacos;
 
-use super::{SkiaRenderer, VSync, WindowConfig, WindowConfigType};
+use super::{RendererSettings, SkiaRenderer, VSync, WindowConfig, WindowConfigType};
 
-use crate::{profiling::tracy_gpu_zone, window::UserEvent};
+use crate::{profiling::tracy_gpu_zone, settings::SETTINGS, window::UserEvent};
 
 #[cfg(feature = "gpu_profiling")]
 use crate::profiling::{opengl::create_opengl_gpu_context, GpuCtx};
@@ -276,13 +276,26 @@ fn create_surface(
  let width = NonZeroU32::new(size.width).unwrap();
  let height = NonZeroU32::new(size.height).unwrap();
  GlSurface::resize(window_surface, context, width, height);
+
+ let render_settings = SETTINGS.get::<RendererSettings>();
+
+ let surface_props = SurfaceProps::new_with_text_properties(
+ SurfacePropsFlags::default(),
+ PixelGeometry::default(),
+ render_settings.text_contrast,
+ render_settings.text_gamma,
+ );
+
+ // NOTE: It would be much better to render using a linear gamma format, and SRGB backbuffer
+ // format But currently the Skia glyph atlas uses a 32-bit linear format texture, so some color
+ // precision is lost, and the font colors will be slightly off.
  wrap_backend_render_target(
  gr_context,
  &backend_render_target,
  SurfaceOrigin::BottomLeft,
  ColorType::RGBA8888,
- None,
- None,
+ ColorSpace::new_srgb(),
+ Some(surface_props).as_ref(),
  )
- .expect("Could not create skia surface")
+ .expect("Could not create skia backend render target")
 }

src/window/window_wrapper.rs

@@ -13,7 +13,10 @@ use crate::windows_utils::{register_right_click, unregister_right_click};
 use crate::{
  bridge::{send_ui, ParallelCommand, SerialCommand},
  profiling::{tracy_frame, tracy_gpu_collect, tracy_gpu_zone, tracy_plot, tracy_zone},
- renderer::{create_skia_renderer, DrawCommand, Renderer, SkiaRenderer, VSync, WindowConfig},
+ renderer::{
+ create_skia_renderer, DrawCommand, Renderer, RendererSettingsChanged, SkiaRenderer, VSync,
+ WindowConfig,
+ },
  settings::{
  clamped_grid_size, FontSettings, HotReloadConfigs, SettingsChanged, DEFAULT_GRID_SIZE,
  MIN_GRID_SIZE, SETTINGS,
@@ -276,6 +279,16 @@ impl WinitWindowWrapper {
  self.macos_feature.handle_settings_changed(changed_setting);
  }
 
+ fn handle_render_settings_changed(&mut self, changed_setting: RendererSettingsChanged) {
+ match changed_setting {
+ RendererSettingsChanged::TextGamma(..) | RendererSettingsChanged::TextContrast(..) => {
+ self.skia_renderer.resize();
+ self.font_changed_last_frame = true;
+ }
+ _ => {}
+ }
+ }
+
  pub fn handle_title_changed(&mut self, new_title: String) {
  self.title = new_title;
  self.skia_renderer.window().set_title(&self.title);
@@ -399,6 +412,9 @@ impl WinitWindowWrapper {
  Event::UserEvent(UserEvent::SettingsChanged(SettingsChanged::Window(e))) => {
  self.handle_window_settings_changed(e);
  }
+ Event::UserEvent(UserEvent::SettingsChanged(SettingsChanged::Renderer(e))) => {
+ self.handle_render_settings_changed(e);
+ }
  Event::UserEvent(UserEvent::ConfigsChanged(config)) => {
  self.handle_config_changed(*config);
  }

website/docs/configuration.md

@@ -71,10 +71,10 @@ as such it's also documented in `:h guifont`. But to sum it up and also add Neov
  - alias
  - `#h-X` (available since 0.10.2) - Sets level of glyph outline adjustment, while `X` is
  a type of hinting:
- - full (default)
+ - full
  - normal
  - slight
- - none
+ - none (default)
 - Some examples:
  - `Hack,Noto_Color_Emoji:h12:b` — Hack at size 12 in bold, with Noto Color Emoji as fallback
  should Hack fail to contain any glyph.
@@ -119,6 +119,32 @@ this][scale-runtime] for a nice recipe to bind this to a hotkey.
 
 [scale-runtime]: faq.md#how-can-i-dynamically-change-the-scale-at-runtime
 
+#### Text Gamma and Contrast
+
+VimScript:
+
+```vim
+let g:neovide_text_gamma = 0.0
+let g:neovide_text_contrast = 0.5
+```
+
+Lua:
+
+```lua
+vim.g.neovide_text_gamma = 0.0
+vim.g.neovide_text_contrast = 0.5
+```
+
+**Unreleased yet.**
+
+You can fine tune the gamma and contrast of the text to your liking. The defaults is a good
+compromise that gives readable text on all backgrounds and an accurate color representation. But if
+that doesn't suit you, and you want to emulate the Alacritty font rendering for example you can use
+a gamma of 0.8 and a contrast of 0.1.
+
+Note a gamma of 0.0, means standard sRGB gamma or 2.2. Also note that these settings don't
+necessarily apply immediately due to caching of the fonts.
+
 #### Padding
 
 VimScript: