enable orgmode latex preview to support retina on mac

1. enable orgmode latex preview to support retina on mac

1 enable orgmode latex preview to support retina on mac

By default orgmode latex preview do not support retina, so on mac with retina screen, latex preview will be fuzzy.
However, we can hack org.el to achieve the function. Just follow steps below:

1.1 get the proper version of emacs

To instead use the Yamamoto Mitsuharu version of Emacs 25.1 (with more mac-specific features):

brew tap railwaycat/emacsmacport
brew install emacs-mac

and finally link it to your Applications folder:

brew linkapps emacs-mac

this version emacs will support retina image display.

1.2 change org-format-latex-options

change scale from 1.0 to 2.0, to generate 2x size image.

1.3 delete org.elc

1.4 add function to org.el

(defun galaxy-compose-image-filename-2x(image-file-name)
(concat (file-name-directory image-file-name) (file-name-base image-file-name) "@2x." (file-name-extension image-file-name)))

and eval the function.

1.5 modify function org-format-latex

change fragment:

(unless (file-exists-p movefile)
(org-create-formula-image value movefile options forbuffer processing-type)

(unless (file-exists-p movefile)
(org-create-formula-image value movefile options forbuffer processing-type)
(setq filename-2x (galaxy-compose-image-filename-2x movefile))
(rename-file movefile filename-2x)
(call-process-shell-command "convert" nil nil nil nil (concat """ filename-2x "" -scale "50%" -quality "100%"" ) (concat """ movefile """ )))