Specify deifferent minification and magnification filters (#2224)

* Specify deifferent minification and magnification filters

* Fixes

* Update changelogs

* Doctest fixes

* Add deprecation notice for RetainedImage::with_texture_filter

crates/epaint/CHANGELOG.md

@@ -13,6 +13,7 @@ All notable changes to the epaint crate will be documented in this file.
 * Added `epaint::hex_color!` to create `Color32`'s from hex strings under the `color-hex` feature ([#1596](https://github.com/emilk/egui/pull/1596)).
 * Optimize tessellation of filled circles by 10x or more ([#1616](https://github.com/emilk/egui/pull/1616)).
 * Added opt-in feature `deadlock_detection` to detect double-lock of mutexes on the same thread ([#1619](https://github.com/emilk/egui/pull/1619)).
+* Texture loading now takes a `TexureOptions` with minification and magnification filters ([#2224](https://github.com/emilk/egui/pull/2224)).
 
 
 ## 0.18.1 - 2022-05-01

crates/epaint/src/image.rs

@@ -1,4 +1,4 @@
-use crate::{textures::TextureFilter, Color32};
+use crate::{textures::TextureOptions, Color32};
 
 /// An image stored in RAM.
 ///
@@ -291,7 +291,7 @@ pub struct ImageDelta {
     /// If [`Self::pos`] is `Some`, this describes a patch of the whole image starting at [`Self::pos`].
     pub image: ImageData,
 
-    pub filter: TextureFilter,
+    pub options: TextureOptions,
 
     /// If `None`, set the whole texture to [`Self::image`].
     ///
@@ -301,19 +301,19 @@ pub struct ImageDelta {
 
 impl ImageDelta {
     /// Update the whole texture.
-    pub fn full(image: impl Into<ImageData>, filter: TextureFilter) -> Self {
+    pub fn full(image: impl Into<ImageData>, options: TextureOptions) -> Self {
         Self {
             image: image.into(),
-            filter,
+            options,
             pos: None,
         }
     }
 
     /// Update a sub-region of an existing texture.
-    pub fn partial(pos: [usize; 2], image: impl Into<ImageData>, filter: TextureFilter) -> Self {
+    pub fn partial(pos: [usize; 2], image: impl Into<ImageData>, options: TextureOptions) -> Self {
         Self {
             image: image.into(),
-            filter,
+            options,
             pos: Some(pos),
         }
     }

crates/epaint/src/texture_atlas.rs

@@ -1,6 +1,6 @@
 use emath::{remap_clamp, Rect};
 
-use crate::{textures::TextureFilter, FontImage, ImageDelta};
+use crate::{FontImage, ImageDelta};
 
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 struct Rectu {
@@ -174,16 +174,18 @@ impl TextureAtlas {
 
     /// Call to get the change to the image since last call.
     pub fn take_delta(&mut self) -> Option<ImageDelta> {
+        let texture_options = crate::textures::TextureOptions::LINEAR;
+
         let dirty = std::mem::replace(&mut self.dirty, Rectu::NOTHING);
         if dirty == Rectu::NOTHING {
             None
         } else if dirty == Rectu::EVERYTHING {
-            Some(ImageDelta::full(self.image.clone(), TextureFilter::Linear))
+            Some(ImageDelta::full(self.image.clone(), texture_options))
         } else {
             let pos = [dirty.min_x, dirty.min_y];
             let size = [dirty.max_x - dirty.min_x, dirty.max_y - dirty.min_y];
             let region = self.image.region(pos, size);
-            Some(ImageDelta::partial(pos, region, TextureFilter::Linear))
+            Some(ImageDelta::partial(pos, region, texture_options))
         }
     }
 

crates/epaint/src/texture_handle.rs

@@ -1,7 +1,7 @@
 use std::sync::Arc;
 
 use crate::{
-    emath::NumExt, mutex::RwLock, textures::TextureFilter, ImageData, ImageDelta, TextureId,
+    emath::NumExt, mutex::RwLock, textures::TextureOptions, ImageData, ImageDelta, TextureId,
     TextureManager,
 };
 
@@ -66,10 +66,10 @@ impl TextureHandle {
     }
 
     /// Assign a new image to an existing texture.
-    pub fn set(&mut self, image: impl Into<ImageData>, filter: TextureFilter) {
+    pub fn set(&mut self, image: impl Into<ImageData>, options: TextureOptions) {
         self.tex_mngr
             .write()
-            .set(self.id, ImageDelta::full(image.into(), filter));
+            .set(self.id, ImageDelta::full(image.into(), options));
     }
 
     /// Assign a new image to a subregion of the whole texture.
@@ -77,11 +77,11 @@ impl TextureHandle {
         &mut self,
         pos: [usize; 2],
         image: impl Into<ImageData>,
-        filter: TextureFilter,
+        options: TextureOptions,
     ) {
         self.tex_mngr
             .write()
-            .set(self.id, ImageDelta::partial(pos, image.into(), filter));
+            .set(self.id, ImageDelta::partial(pos, image.into(), options));
     }
 
     /// width x height

crates/epaint/src/textures.rs

@@ -26,7 +26,7 @@ impl TextureManager {
     /// MUST have a white pixel at (0,0) ([`crate::WHITE_UV`]).
     ///
     /// The texture is given a retain-count of `1`, requiring one call to [`Self::free`] to free it.
-    pub fn alloc(&mut self, name: String, image: ImageData, filter: TextureFilter) -> TextureId {
+    pub fn alloc(&mut self, name: String, image: ImageData, options: TextureOptions) -> TextureId {
         let id = TextureId::Managed(self.next_id);
         self.next_id += 1;
 
@@ -35,10 +35,10 @@ impl TextureManager {
             size: image.size(),
             bytes_per_pixel: image.bytes_per_pixel(),
             retain_count: 1,
-            filter,
+            options,
         });
 
-        self.delta.set.push((id, ImageDelta::full(image, filter)));
+        self.delta.set.push((id, ImageDelta::full(image, options)));
         id
     }
 
@@ -131,8 +131,50 @@ pub struct TextureMeta {
     /// Free when this reaches zero.
     pub retain_count: usize,
 
-    /// The texture filtering mode to use when rendering
-    pub filter: TextureFilter,
+    /// The texture filtering mode to use when rendering.
+    pub options: TextureOptions,
+}
+
+impl TextureMeta {
+    /// Size in bytes.
+    /// width x height x [`Self::bytes_per_pixel`].
+    pub fn bytes_used(&self) -> usize {
+        self.size[0] * self.size[1] * self.bytes_per_pixel
+    }
+}
+
+// ----------------------------------------------------------------------------
+
+/// How the texture texels are filtered.
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+pub struct TextureOptions {
+    /// How to filter when magnifying (when texels are larger than pixels).
+    pub magnification: TextureFilter,
+
+    /// How to filter when minifying (when texels are smaller than pixels).
+    pub minification: TextureFilter,
+}
+
+impl TextureOptions {
+    /// Linear magnification and minification.
+    pub const LINEAR: Self = Self {
+        magnification: TextureFilter::Linear,
+        minification: TextureFilter::Linear,
+    };
+
+    /// Nearest magnification and minification.
+    pub const NEAREST: Self = Self {
+        magnification: TextureFilter::Nearest,
+        minification: TextureFilter::Nearest,
+    };
+}
+
+impl Default for TextureOptions {
+    /// The default is linear for both magnification and minification.
+    fn default() -> Self {
+        Self::LINEAR
+    }
 }
 
 /// How the texture texels are filtered.
@@ -146,25 +188,9 @@ pub enum TextureFilter {
     Nearest,
 
     /// Linearly interpolate the nearest neighbors, creating a smoother look when zooming in and out.
-    ///
-    /// This is the default.
     Linear,
 }
 
-impl Default for TextureFilter {
-    fn default() -> Self {
-        Self::Linear
-    }
-}
-
-impl TextureMeta {
-    /// Size in bytes.
-    /// width x height x [`Self::bytes_per_pixel`].
-    pub fn bytes_used(&self) -> usize {
-        self.size[0] * self.size[1] * self.bytes_per_pixel
-    }
-}
-
 // ----------------------------------------------------------------------------
 
 /// What has been allocated and freed during the last period.