From 4861d93c80a79a5c78b04b48ae4dd5eb5103abef Mon Sep 17 00:00:00 2001
From: Schrottkatze <git@schrottkatze.de>
Date: Wed, 22 May 2024 09:42:40 +0200
Subject: [PATCH] add position matrix

---
 src/components.rs    | 19 +++++++++++--------
 src/img_processor.rs | 28 ++++++++++++++++++++++++----
 src/lib.rs           |  6 +++---
 3 files changed, 38 insertions(+), 15 deletions(-)

diff --git a/src/components.rs b/src/components.rs
index 1212ab6..28f23af 100644
--- a/src/components.rs
+++ b/src/components.rs
@@ -5,18 +5,21 @@ pub fn mat_editor<const R: usize, const C: usize>(
     ui: &mut egui::Ui,
     mat: &mut SMatrix<f32, R, C>,
     id: &str,
+    skip_last: bool,
 ) -> egui::Response {
     egui::Grid::new(id)
         .show(ui, |ui| {
             mat.row_iter_mut().enumerate().for_each(|(i, mut row)| {
-                row.iter_mut().for_each(|item| {
-                    ui.add(
-                        egui::DragValue::new(item)
-                            .speed(0.01)
-                            .clamp_range(-10.0..=10.0),
-                    );
-                });
-                ui.end_row();
+                if !skip_last || i + 1 < R {
+                    row.iter_mut().for_each(|item| {
+                        ui.add(
+                            egui::DragValue::new(item)
+                                .speed(0.01)
+                                .clamp_range(-10.0..=10.0),
+                        );
+                    });
+                    ui.end_row();
+                }
             })
         })
         .response
diff --git a/src/img_processor.rs b/src/img_processor.rs
index 265be19..0dfb20a 100644
--- a/src/img_processor.rs
+++ b/src/img_processor.rs
@@ -5,14 +5,14 @@ use std::{
 
 use eframe::egui::{self, TextureOptions};
 use image::{DynamicImage, Pixel, Rgb, Rgb32FImage};
-use nalgebra::{SMatrix, Vector4};
+use nalgebra::{SMatrix, Vector3, Vector4};
 use rayon::prelude::*;
 
 use image::EncodableLayout;
 struct ProcessorInstruction {
     img: Arc<Rgb32FImage>,
     color_matrix: SMatrix<f32, 3, 4>,
-    pos_matrix: SMatrix<f32, 2, 3>,
+    pos_matrix: SMatrix<f32, 3, 3>,
     ret: oneshot::Sender<(egui::TextureHandle, (f32, f32))>,
     ctx: egui::Context,
     handle: Option<egui::TextureHandle>,
@@ -37,7 +37,27 @@ impl Processor {
             {
                 let (width, height) = img.dimensions();
 
-                let mut r = (*img).clone();
+                // let mut r = (*img).clone();
+                let mut r = Rgb32FImage::new(width, height);
+                if !pos_matrix.is_identity(f32::EPSILON) && pos_matrix.is_invertible() {
+                    let mut inv_mat = pos_matrix.try_inverse().unwrap();
+                    let mut cols_mut = inv_mat.column_part_mut(2, 2);
+                    *(cols_mut.get_mut(0).unwrap()) *= width as f32;
+                    *(cols_mut.get_mut(1).unwrap()) *= height as f32;
+
+                    r.par_enumerate_pixels_mut().for_each(|(x, y, px)| {
+                        let r = inv_mat * Vector3::new(x as f32, y as f32, 1.0);
+                        *px = if r.x.is_sign_positive() && r.y.is_sign_positive() {
+                            *img.get_pixel_checked(r.x as u32, r.y as u32)
+                                .unwrap_or(&Rgb([0., 0., 0.]))
+                        } else {
+                            Rgb([0., 0., 0.])
+                        };
+                    });
+                } else {
+                    r = (*img).clone()
+                }
+
                 if !color_matrix.is_identity(f32::EPSILON) {
                     r.par_pixels_mut().for_each(|px| {
                         *px = Rgb::from(
@@ -76,7 +96,7 @@ impl Processor {
         &self,
         img: Arc<Rgb32FImage>,
         color_matrix: SMatrix<f32, 3, 4>,
-        pos_matrix: SMatrix<f32, 2, 3>,
+        pos_matrix: SMatrix<f32, 3, 3>,
         ctx: egui::Context,
         handle: Option<egui::TextureHandle>,
     ) -> oneshot::Receiver<(egui::TextureHandle, (f32, f32))> {
diff --git a/src/lib.rs b/src/lib.rs
index 15a9842..f119682 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,7 +16,7 @@ mod img_processor;
 
 pub struct App {
     color_matrix: SMatrix<f32, 3, 4>,
-    pos_matrix: SMatrix<f32, 2, 3>,
+    pos_matrix: SMatrix<f32, 3, 3>,
     file_dialog: FileDialog,
     new_file: Option<PathBuf>,
     cur_img: Option<Arc<Rgb32FImage>>,
@@ -74,11 +74,11 @@ impl eframe::App for App {
             let old_pos_mat = self.pos_matrix;
             ui.label("Color Matrix Editor");
             let color_mat_edited =
-                components::mat_editor(ui, &mut self.color_matrix, "color_matrix").dragged();
+                components::mat_editor(ui, &mut self.color_matrix, "color_matrix", false).dragged();
             ui.add_space(8.);
             ui.label("Position Matrix Editor");
             let pos_mat_edited =
-                components::mat_editor(ui, &mut self.pos_matrix, "pos_matrix").dragged();
+                components::mat_editor(ui, &mut self.pos_matrix, "pos_matrix", true).dragged();
             mats_changed |= old_color_mat == self.color_matrix || old_pos_mat == self.pos_matrix;
 
             if mats_changed