add form generation via typst

this closes #3

README.md

@@ -38,7 +38,18 @@ which is self-documented. The following is for the wasm web application.
 
 We need a template which tells us where every answer box is located on the page
 and where three large round circles on the page are to identify the position of
-a scan. For this, go to the *Create Template* view. Upload an image file (like .png) of
+a scan.
+
+You have two options for this. You can either use the *Create Form* view, which
+generates a PDF file to print (in A4) and the corresponding `template.json` file
+that you need to provide when you grade the exam.
+
+#### Using a custom form
+
+If you want to use a custom form, this is entirely possible, but significantly
+more painful.
+
+For this, go to the *Create Template* view. Upload an image file (like .png) of
 an empty form, preferably directly converted from a PDF file so nothing is
 skewed by a scanner. You need to enter the following information:
 
@@ -61,6 +72,10 @@ After entering this data and uploading an image file, you can hit "Preview" to
 see if everything goes well. You can then download the configuration to
 `template.json`
 
+If this does not work in your case, you will need to adapt the `template.json`
+by hand and provide the coordinates of the bounding boxes of all bubbles (top
+left corner and bottom right corner).
+
 ### The exam key
 
 Go to *Create Key*. Enter how many versions you have and enter the correct
@@ -103,5 +118,5 @@ correct answer, meaning that the selected bubble is elsewhere.
 
 ## Acknowledgements
 
-This project uses ![typst](https://github.com/typst/typst) for typesetting and
+This project uses [typst](https://github.com/typst/typst) for typesetting and
 ships with copies of the Linux Biolinum font by Philipp H Poll.

src/webapp/create_form.rs

@@ -0,0 +1,151 @@
+use crate::image_helpers::binary_image_from_image;
+use crate::scan::Scan;
+use crate::template::Template;
+use crate::typst_helpers::{typst_frame_to_template, TypstWrapper};
+use crate::webapp::utils::{download_button, QuestionSettings};
+use eframe::egui::{Context, ScrollArea};
+use eframe::Frame;
+
+pub struct CreateForm {
+    pub question_settings: QuestionSettings,
+    pub preview: Option<egui::TextureHandle>,
+    pub pdf: Option<Vec<u8>>,
+    pub template: Option<Template>,
+    pub png: Option<Vec<u8>>,
+}
+
+impl Default for CreateForm {
+    fn default() -> Self {
+        Self {
+            question_settings: QuestionSettings::default(),
+            preview: None,
+            pdf: None,
+            template: None,
+            png: None,
+        }
+    }
+}
+
+impl CreateForm {
+    pub fn update(&mut self, ctx: &Context, _frame: &mut Frame) {
+        eframe::egui::SidePanel::left("settings_panel")
+            .resizable(false)
+            .default_width(200.0)
+            .show(ctx, |ui| {
+                ui.heading("Settings");
+                ui.add_space(10.0);
+
+                ui.add(
+                    egui::Slider::new(&mut self.question_settings.num_qs, 1..=50)
+                        .text("Number of Questions"),
+                );
+
+                ui.add(
+                    egui::Slider::new(&mut self.question_settings.num_id_qs, 1..=15)
+                        .text("ID Questions"),
+                );
+
+                ui.add(
+                    egui::Slider::new(&mut self.question_settings.num_versions, 1..=8)
+                        .text("Versions"),
+                );
+
+                ui.add(
+                    egui::Slider::new(&mut self.question_settings.num_answers, 2..=8)
+                        .text("Answers per Question"),
+                );
+
+                ui.add_space(20.0);
+
+                if ui.button("Generate").clicked() {
+                    let tmpl = include_str!("../../assets/formtemplate.typ");
+
+                    let code = format!(
+                        r#"
+#let num_qs = {}
+#let num_idqs = {}
+#let num_answers = {}
+#let num_versions = {}
+{}
+"#,
+                        self.question_settings.num_qs,
+                        self.question_settings.num_id_qs,
+                        self.question_settings.num_answers,
+                        self.question_settings.num_versions,
+                        tmpl
+                    );
+                    let wrapper = TypstWrapper::new(code);
+
+                    let document = typst::compile(&wrapper)
+                        .output
+                        .expect("Error from Typst. This really should not happen. So sorry.");
+
+                    let scale = 3.0;
+                    let template = typst_frame_to_template(&document.pages[0].frame, scale);
+                    self.template = Some(template.clone());
+                    let pdf =
+                        typst_pdf::pdf(&document, &typst_pdf::PdfOptions::default()).expect("bla");
+
+                    self.pdf = Some(pdf.clone());
+
+                    let png = typst_render::render(&document.pages[0], scale as f32)
+                        .encode_png()
+                        .unwrap();
+
+                    self.png = Some(png.clone());
+
+                    let dynimage = image::load_from_memory(&png).unwrap();
+                    let scan = Scan {
+                        img: binary_image_from_image(dynimage),
+                        transformation: None,
+                    };
+                    let circled = scan.circle_everything(&template);
+                    let dynamic_image = image::DynamicImage::ImageRgb8(circled);
+
+                    let size = [dynamic_image.width() as _, dynamic_image.height() as _];
+                    let image_buffer = dynamic_image.to_rgba8();
+                    let pixels = image_buffer.as_flat_samples();
+
+                    let texture = ctx.load_texture(
+                        "preview_image",
+                        egui::ColorImage::from_rgba_unmultiplied(size, pixels.as_slice()),
+                        egui::TextureOptions::default(),
+                    );
+                    self.preview = Some(texture);
+
+                    download_button(
+                        ui,
+                        "💾 Save Template as json",
+                        serde_json::to_vec(&template).unwrap(),
+                    );
+                    download_button(ui, "💾 Save form as PNG", png);
+                }
+
+                if let Some(template) = &self.template {
+                    download_button(
+                        ui,
+                        "💾 Save template as JSON",
+                        serde_json::to_vec(&template).unwrap(),
+                    );
+                }
+                if let Some(pdf) = &self.pdf {
+                    download_button(ui, "💾 Save form as PDF", pdf.to_vec());
+                }
+                if let Some(png) = &self.png {
+                    download_button(ui, "💾 Save form as PNG", png.to_vec());
+                }
+            });
+
+        eframe::egui::CentralPanel::default().show(ctx, |ui| {
+            ui.heading("Preview");
+            if let Some(texture) = &self.preview {
+                ScrollArea::both().show(ui, |ui| {
+                    // Display the rendered image or a placeholder if no image is available
+                    ui.add(egui::Image::new(texture));
+                });
+            } else {
+                ui.label("No preview available");
+            }
+        });
+    }
+}

src/webapp/create_template.rs

@@ -2,7 +2,9 @@ use crate::image_helpers::{binary_image_from_image, rgb_to_egui_color_image};
 use crate::point::Point;
 use crate::scan::Scan;
 use crate::template::Template;
-use crate::webapp::utils::{download_button, template_from_settings, upload_button, FileType};
+use crate::webapp::utils::{
+    download_button, template_from_settings, upload_button, FileType, QuestionSettings,
+};
 use eframe::egui::{CentralPanel, Context, ScrollArea, SidePanel, TextEdit, Ui};
 use eframe::Frame;
 use tokio::sync::mpsc::{channel, Receiver, Sender};
@@ -265,25 +267,6 @@ impl CreateTemplate {
         });
     }
 }
-
-pub struct QuestionSettings {
-    pub num_qs: u32,
-    pub num_id_qs: u32,
-    pub num_versions: u32,
-    pub num_answers: u32,
-}
-
-impl Default for QuestionSettings {
-    fn default() -> Self {
-        Self {
-            num_qs: 20,
-            num_id_qs: 9,
-            num_versions: 4,
-            num_answers: 5,
-        }
-    }
-}
-
 pub struct LayoutSettings {
     pub box_height: u32,
     pub box_width: u32,

src/webapp/mod.rs

@@ -1,4 +1,5 @@
 #![cfg(target_arch = "wasm32")]
+pub mod create_form;
 pub mod create_key;
 pub mod create_template;
 pub mod generate_report;

src/webapp/utils.rs

@@ -2,9 +2,7 @@ use crate::point::Point;
 use crate::template::Box;
 use crate::template::Question;
 use crate::template::Template;
-use crate::webapp::create_template::{
-    CircleSettings, LayoutSettings, PositionSettings, QuestionSettings,
-};
+use crate::webapp::create_template::{CircleSettings, LayoutSettings, PositionSettings};
 use std::future::Future;
 use tokio::sync::mpsc::Sender;
 
@@ -18,6 +16,24 @@ pub fn execute<F: Future<Output = ()> + 'static>(f: F) {
     wasm_bindgen_futures::spawn_local(f);
 }
 
+pub struct QuestionSettings {
+    pub num_qs: u32,
+    pub num_id_qs: u32,
+    pub num_versions: u32,
+    pub num_answers: u32,
+}
+
+impl Default for QuestionSettings {
+    fn default() -> Self {
+        Self {
+            num_qs: 20,
+            num_id_qs: 9,
+            num_versions: 4,
+            num_answers: 5,
+        }
+    }
+}
+
 pub fn upload_button(
     ui: &mut egui::Ui,
     ctx: &egui::Context,

src/webapp/webapp.rs

@@ -1,6 +1,7 @@
 use eframe::egui;
 use eframe::egui::Context;
 
+use crate::webapp::create_form::CreateForm;
 use crate::webapp::create_key::CreateKey;
 use crate::webapp::create_template::CreateTemplate;
 
@@ -11,13 +12,15 @@ pub struct WebApp {
     current_view: ViewType,
     generate_report: GenerateReport,
     create_template: CreateTemplate,
+    create_form: CreateForm,
     create_key: CreateKey,
     help: Help,
 }
 
 enum ViewType {
     GenerateReport,
     CreateTemplate,
+    CreateForm,
     CreateKey,
     Help,
 }
@@ -27,6 +30,7 @@ impl Default for WebApp {
         Self {
             current_view: ViewType::Help,
             generate_report: GenerateReport::default(),
+            create_form: CreateForm::default(),
             create_template: CreateTemplate::default(),
             create_key: CreateKey::default(),
             help: Help::default(),
@@ -42,6 +46,9 @@ impl eframe::App for WebApp {
                 if ui.button("Generate Report").clicked() {
                     self.current_view = ViewType::GenerateReport;
                 }
+                if ui.button("Create Form").clicked() {
+                    self.current_view = ViewType::CreateForm;
+                }
                 if ui.button("Create Template").clicked() {
                     self.current_view = ViewType::CreateTemplate;
                 }
@@ -56,6 +63,7 @@ impl eframe::App for WebApp {
 
         match self.current_view {
             ViewType::GenerateReport => self.generate_report.update(ctx, frame),
+            ViewType::CreateForm => self.create_form.update(ctx, frame),
             ViewType::CreateTemplate => self.create_template.update(ctx, frame),
             ViewType::CreateKey => self.create_key.update(ctx, frame),
             ViewType::Help => self.help.update(ctx, frame),