Support high-resolution displays

3 files changed, 39 insertions, 3 deletions

diff --git a/lisp/pdf-info.el b/lisp/pdf-info.el
index 3eeacf8..6dd7ff6 100644
--- a/lisp/pdf-info.el
+++ b/lisp/pdf-info.el
@@ -1594,7 +1594,7 @@ Return the data of the corresponding PNG image."
     'renderpage
     (pdf-info--normalize-file-or-buffer file-or-buffer)
     page
-    width
+    (* width (pdf-util-frame-scale-factor))
     (let (transformed)
       (while (cdr commands)
         (let ((kw (pop commands))
diff --git a/lisp/pdf-util.el b/lisp/pdf-util.el
index a521ec6..3955fb6 100644
--- a/lisp/pdf-util.el
+++ b/lisp/pdf-util.el
@@ -37,6 +37,8 @@
 (declare-function pdf-view-current-overlay "pdf-view")
 (declare-function pdf-cache-pagesize "pdf-cache")
 
+(declare-function pdf-view-image-type "pdf-view")
+
 
 
 ;; * ================================================================== *
@@ -918,6 +920,35 @@ See also `regexp-quote'."
       (push ch escaped))
     (apply 'string (nreverse escaped))))
 
+(defun pdf-util-frame-ppi ()
+  "Return the PPI of the current frame."
+  (let* ((props (frame-monitor-attributes))
+         (px (nthcdr 2 (alist-get 'geometry props)))
+         (mm (alist-get 'mm-size props))
+         (dp (sqrt (+ (expt (nth 0 px) 2)
+                      (expt (nth 1 px) 2))))
+         (di (sqrt (+ (expt (/ (nth 0 mm) 25.4) 2)
+                      (expt (/ (nth 1 mm) 25.4) 2)))))
+    (/ dp di)))
+
+(defvar pdf-view-use-scaling)
+
+(defun pdf-util-frame-scale-factor ()
+  "Return the frame scale factor depending on the image type used for display.
+When `pdf-view-use-scaling' is non-nil and imagemagick or
+image-io are used as the image type for display, return the
+backing-scale-factor of the frame if available. If a
+backing-scale-factor attribute isn't available, return 2 if the
+frame's PPI is larger than 180. Otherwise, return 1."
+  (if (and pdf-view-use-scaling
+           (memq (pdf-view-image-type) '(imagemagick image-io))
+           (fboundp 'frame-monitor-attributes))
+      (or (cdr (assq 'backing-scale-factor (frame-monitor-attributes)))
+          (if (>= (pdf-util-frame-ppi) 180)
+              2
+            1))
+    1))
+
 
 ;; * ================================================================== *
 ;; * Imagemagick's convert
diff --git a/lisp/pdf-view.el b/lisp/pdf-view.el
index cc85c05..d4367fd 100644
--- a/lisp/pdf-view.el
+++ b/lisp/pdf-view.el
@@ -903,6 +903,8 @@ See also `pdf-view-use-imagemagick'."
   (cond ((and pdf-view-use-imagemagick
               (fboundp 'imagemagick-types))
          'imagemagick)
+        ((image-type-available-p 'image-io)
+         'image-io)
         ((image-type-available-p 'png)
          'png)
         ((fboundp 'imagemagick-types)
@@ -912,8 +914,8 @@ See also `pdf-view-use-imagemagick'."
 
 (defun pdf-view-use-scaling-p ()
   "Return t if scaling should be used."
-  (and (eq 'imagemagick
-           (pdf-view-image-type))
+  (and (memq (pdf-view-image-type)
+             '(imagemagick image-io))
        pdf-view-use-scaling))
 
 (defmacro pdf-view-create-image (data &rest props)
@@ -933,6 +935,9 @@ See also `pdf-view-use-imagemagick'."
                   (* 2 (car size)))))
          (hotspots (pdf-view-apply-hotspot-functions
                     window page size)))
+    (when (and (eq (framep-on-display) 'mac)
+               (= (pdf-util-frame-scale-factor) 2))
+      (put-text-property 0 1 :data-2x data data))
     (pdf-view-create-image data
       :width (car size)
       :map hotspots