From dad83306bbff0677bc32c538f8753d714ee3c45b Mon Sep 17 00:00:00 2001
From: Dimitri Lozeve <dimitri@lozeve.com>
Date: Thu, 16 Apr 2020 15:23:08 +0200
Subject: [PATCH] Add mathpix

---
 .gitignore           |  2 +-
 init.el              | 15 ++++++--
 site-lisp/mathpix.el | 90 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 102 insertions(+), 5 deletions(-)
 create mode 100644 site-lisp/mathpix.el

diff --git a/.gitignore b/.gitignore
index 8660bba..7b23935 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,4 +22,4 @@ elpy/
 org-clock-save.el
 forge-database.sqlite
 custom.el
-email.el
+secrets.el
diff --git a/init.el b/init.el
index bc63d02..2e77d38 100644
--- a/init.el
+++ b/init.el
@@ -386,6 +386,13 @@
   :config
   (setq twittering-reverse-mode t))
 
+(use-package mathpix.el
+  :load-path "site-lisp"
+  ;; You also need to configure `mathpix-app-id` and
+  ;; `mathpix-app-key`, for instance in secrets.el
+  :bind
+  ("C-x m" . mathpix-screenshot))
+
 ;; Org-mode
 ;; Pour accéder rapidement à l'organisation
 (defun gtd ()
@@ -576,11 +583,11 @@
     (kill-ring-save (point-min) (point-max))))
 
 
-;; email configuration file
-(setq email-file (expand-file-name "email.el" user-emacs-directory))
+;; configuration file for secrets (API keys, etc)
+(setq secrets-file (expand-file-name "secrets.el" user-emacs-directory))
 
-(when (file-exists-p email-file)
-  (load email-file))
+(when (file-exists-p secrets-file)
+  (load secrets-file))
 
 
 ;; config changes made through the customize UI will be stored here
diff --git a/site-lisp/mathpix.el b/site-lisp/mathpix.el
new file mode 100644
index 0000000..fcd5053
--- /dev/null
+++ b/site-lisp/mathpix.el
@@ -0,0 +1,90 @@
+;;; mathpix.el --- Mathpix API from Emacs
+
+;;; Commentary:
+;; This package provides an interface similar to the Mathpix snipping tool.
+;;
+;; mathpix-screenshot prompts for a screenshot, which is sent for processing
+;; via Mathpix's API.
+;;
+;;  Heavily adapted from org-download.
+
+(require 'json)
+
+(defcustom mathpix-app-id nil
+  "App ID for Mathpix.")
+
+(defcustom mathpix-app-key nil
+  "App key for Mathpix.")
+
+;; From org-download
+(defcustom mathpix-screenshot-method "gnome-screenshot -a -f %s"
+  "The tool to capture screenshots."
+  :type '(choice
+          (const :tag "gnome-screenshot" "gnome-screenshot -a -f %s")
+          (const :tag "scrot" "scrot -s %s")
+          (const :tag "gm" "gm import %s")
+          (const :tag "imagemagick/import" "import %s")
+          (const :tag "imagemagick/import + xclip to save to clipboard"
+                 "export filename=\"%s\"; import png:\"$filename\" ;xclip -selection clipboard -target image/png -filter < \"$filename\" &>/dev/null")
+          (const :tag "xfce4-screenshooter" "xfce4-screenshooter -r -o cat > %s")
+          ;; screenshot method in ms-windows, /capture=4 stands for interactive.
+          (const :tag "IrfanView" "i_view64 /capture=4 /convert=\"%s\"")
+          ;; screenshot script in osx, -i stands for interactive,
+          ;; press space key to toggle between selection and
+          ;; window/application mode.
+          (const :tag "screencapture" "screencapture -i %s")
+          ;; take an image that is already on the clipboard, for Linux
+          (const :tag "xclip"
+                 "xclip -selection clipboard -t image/png -o > %s")
+          ;; take an image that is already on the clipboard, for Windows
+          (const :tag "imagemagick/convert" "convert clipboard: %s")
+          (function :tag "Custom function")))
+
+(defcustom mathpix-screenshot-file
+  (expand-file-name "mathpix.png" temporary-file-directory)
+  "The file to capture mathpix screenshots"
+  :type 'string)
+
+(defconst mathpix-api-curl-command
+  "curl -s https://api.mathpix.com/v3/latex -X POST -H \"app_id: %s\" -H \"app_key: %s\" -H \"Content-Type: application/json\" --data \"{\\\"src\\\":\\\"%s\\\",\\\"formats\\\": [\\\"latex_styled\\\"],\\\"format_options\\\":{\\\"latex_styled\\\": {\\\"transforms\\\": [\\\"rm_spaces\\\"]}}}\""
+  "The shell executable command to retrieve the results.")
+
+;; screenshot programs have exit-code of 0 even when screenshotting is cancelled.
+;; To save API calls, we use the existence of the file as a check if the user
+;; wants to continue. Hence, we must delete the file after each function call.
+(defun mathpix-screenshot ()
+  "Capture screenshot and send result to Mathpix API."
+  (interactive)
+  (let ((default-directory "~"))
+    (make-directory (file-name-directory mathpix-screenshot-file) t)
+    (if (functionp mathpix-screenshot-method)
+        (funcall mathpix-screenshot-file mathpix-screenshot-file)
+      (shell-command-to-string
+       (format mathpix-screenshot-method mathpix-screenshot-file)))
+    (when (file-exists-p mathpix-screenshot-file)
+      (insert (mathpix-get-result mathpix-screenshot-file))
+      (delete-file mathpix-screenshot-file))))
+
+
+(defun mathpix-get-b64-image (file)
+  "Returns the base-64 image string from file."
+  (with-temp-buffer
+    (insert-file-contents file)
+    (base64-encode-string (buffer-string) t)))
+
+(defun mathpix-get-result (file)
+  "Sends the image to Mathpix API."
+  (let* ((file-extension (file-name-extension file))
+         (image-data (format "data:image/%s;base64,%s" file-extension (mathpix-get-b64-image file)))
+         (command (format mathpix-api-curl-command mathpix-app-id mathpix-app-key image-data))
+         (result (json-read-from-string (shell-command-to-string command))))
+    (let ((error (assoc-default 'error result)))
+      (if error
+          (progn
+            (message "%s" error)
+            "")
+        (assoc-default 'latex_styled result)))))
+
+(provide 'mathpix)
+
+;;; mathpix.el ends here