bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Fu, Yuan]

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In Emacs 27, doc-view doesn’t to image rescaling if imagemagick is not present. However, since we have native image rescaling now, we want to rescale regardless of imagemagick. I also added convenient centering commands to doc-view.el. Note that the patch is made on Emacs master branch.

Yuan



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From 1dced88a90a5cf3e940747d2958b02b95ea3491c Mon Sep 17 00:00:00 2001
From: Yuan Fu <casouri@gmail.com>
Date: Wed, 8 Jul 2020 15:21:48 -0400
Subject: [PATCH] Remove imagemagick code in doc-view and add centering
 commands

The problem with old imagemagick code is that, doc-view checks for
imagemagick and only rescales the image if imagemagic is present.
Now that we have natice rescaling, we want to rescale image regardless.

* lisp/doc-view.el (doc-view-mode-map): Add binding for centering
commands.
(doc-view-mode-p, doc-view-enlarge, doc-view-scale-reset,
doc-view-insert-image): Remove imagemagick code.
(doc-view--auto-center-horizontally,
doc-view--auto-center-vertically): New variables.
(doc-view-toggle-auto-center-page-horizontally,
doc-view-toggle-auto-center-page-vertically,
doc-view-auto-center,
doc-view-center-page-horizontally,
doc-view-center-page-vertically): New functions.
---
 lisp/doc-view.el | 79 ++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 67 insertions(+), 12 deletions(-)

diff --git a/lisp/doc-view.el b/lisp/doc-view.el
index de342f1519..db0e1de233 100644
--- a/lisp/doc-view.el
+++ b/lisp/doc-view.el
@@ -435,6 +435,11 @@ doc-view-mode-map
     (define-key map (kbd "c m")       'doc-view-set-slice-using-mouse)
     (define-key map (kbd "c b")       'doc-view-set-slice-from-bounding-box)
     (define-key map (kbd "c r")       'doc-view-reset-slice)
+    ;; Centering the image
+    (define-key map (kbd "c h")       'doc-view-center-page-horizontally)
+    (define-key map (kbd "c v")       'doc-view-center-page-vertically)
+    (define-key map (kbd "c H")       'doc-view-toggle-auto-center-page-horizontally)
+    (define-key map (kbd "c V")       'doc-view-toggle-auto-center-page-vertically)
     ;; Searching
     (define-key map (kbd "C-s")       'doc-view-search)
     (define-key map (kbd "<find>")    'doc-view-search)
@@ -740,8 +745,7 @@ doc-view-mode-p
 Document types are symbols like `dvi', `ps', `pdf', or `odf' (any
 OpenDocument format)."
   (and (display-graphic-p)
-       (or (image-type-available-p 'imagemagick)
-	   (image-type-available-p 'png))
+       (image-type-available-p 'png)
        (cond
 	((eq type 'dvi)
 	 (and (doc-view-mode-p 'pdf)
@@ -769,10 +773,7 @@ doc-view-shrink-factor
 (defun doc-view-enlarge (factor)
   "Enlarge the document by FACTOR."
   (interactive (list doc-view-shrink-factor))
-  (if (and doc-view-scale-internally
-           (eq (plist-get (cdr (doc-view-current-image)) :type)
-               'imagemagick))
-      ;; ImageMagick supports on-the-fly-rescaling.
+  (if doc-view-scale-internally
       (let ((new (ceiling (* factor doc-view-image-width))))
         (unless (equal new doc-view-image-width)
           (setq-local doc-view-image-width new)
@@ -792,9 +793,7 @@ doc-view-shrink
 (defun doc-view-scale-reset ()
   "Reset the document size/zoom level to the initial one."
   (interactive)
-  (if (and doc-view-scale-internally
-           (eq (plist-get (cdr (doc-view-current-image)) :type)
-               'imagemagick))
+  (if doc-view-scale-internally
       (progn
 	(kill-local-variable 'doc-view-image-width)
 	(doc-view-insert-image
@@ -927,6 +926,63 @@ doc-view-fit-window-to-page
     (when new-frame-params
       (modify-frame-parameters (selected-frame) new-frame-params))))
 
+(defvar-local doc-view--auto-center-horizontally nil
+  "If non-nil, automatically center page horizontally.")
+
+(defvar-local doc-view--auto-center-vertically nil
+  "If non-nil, automatically center page vertically.")
+
+(defun doc-view-toggle-auto-center-page-horizontally ()
+  "Toggle whether to automatically center page horizontally."
+  (interactive)
+  (setq doc-view--auto-center-horizontally
+        (not doc-view--auto-center-horizontally))
+  (message "Auto center horizontally: %s"
+           (if doc-view--auto-center-horizontally
+               "on" "off")))
+
+(defun doc-view-toggle-auto-center-page-vertically ()
+  "Toggle whether to automatically center page vertically."
+  (interactive)
+  (setq doc-view--auto-center-vertically
+        (not doc-view--auto-center-vertically))
+  (message "Auto center vertically: %s"
+           (if doc-view--auto-center-vertically
+               "on" "off")))
+
+(defun doc-view-auto-center ()
+  "Automatically center page."
+  (when doc-view--auto-center-horizontally
+    (doc-view-center-page-horizontally))
+  (when doc-view--auto-center-vertically
+    (doc-view-center-page-vertically)))
+
+(defun doc-view-center-page-horizontally ()
+  "Center page horizontally when page is wider than window."
+  (interactive)
+  (let ((page-width (car (image-size (doc-view-current-image) 'pixel)))
+        (window-width (window-body-width nil 'pixel))
+        ;; How much do we scroll in order to center the page?
+        (pixel-hscroll 0)
+        ;; How many pixels are there in a column?
+        (col-in-pixel (/ (window-body-width nil 'pixel)
+                         (window-body-width nil))))
+    (when (> page-width window-width)
+      (setq pixel-hscroll (/ (- page-width window-width) 2))
+      (set-window-hscroll (selected-window)
+                          (/ pixel-hscroll col-in-pixel)))))
+
+(defun doc-view-center-page-vertically ()
+  "Center page vertically when page is wider than window."
+  (interactive)
+  (let ((page-height (cdr (image-size (doc-view-current-image) 'pixel)))
+        (window-height (window-body-height nil 'pixel))
+        ;; How much do we scroll in order to center the page?
+        (pixel-scroll 0))
+    (when (> page-height window-height)
+      (setq pixel-scroll (/ (- page-height window-height) 2))
+      (set-window-vscroll (selected-window) pixel-scroll 'pixel))))
+
 (defun doc-view-reconvert-doc ()
   "Reconvert the current document.
 Should be invoked when the cached images aren't up-to-date."
@@ -1393,12 +1449,11 @@ doc-view-insert-image
     ;; Only insert the image if the buffer is visible.
     (when (window-live-p (overlay-get ol 'window))
       (let* ((image (if (and file (file-readable-p file))
-			(if (not (and doc-view-scale-internally
-				      (fboundp 'imagemagick-types)))
+			(if (not doc-view-scale-internally)
 			    (apply #'create-image file doc-view--image-type nil args)
 			  (unless (member :width args)
 			    (setq args `(,@args :width ,doc-view-image-width)))
-			  (apply #'create-image file 'imagemagick nil args))))
+			  (apply #'create-image file doc-view--image-type nil args))))
 	     (slice (doc-view-current-slice))
 	     (img-width (and image (car (image-size image))))
 	     (displayed-img-width (if (and image slice)
-- 
2.27.0

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Lars Ingebrigtsen]

"Fu, Yuan" <ykf5041@psu.edu> writes:

> In Emacs 27, doc-view doesn’t to image rescaling if imagemagick is not
> present.  However, since we have native image rescaling now, we want
> to rescale regardless of imagemagick. I also added convenient
> centering commands to doc-view.el. Note that the patch is made on
> Emacs master branch.

The imagemagick fixes look good to me, and the new functionality, too.
But this should probably be done in two separate patches, and the patch
with the new functionality also needs to be documented in the Document
View node in the misc.texi manual.  (And it also needs an etc/NEWS
entry.)

Can you do the patch splitting and documentation additions and resubmit?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Yuan Fu]

> On Aug 5, 2020, at 11:13 AM, Lars Ingebrigtsen <larsi@gnus.org> wrote:
> 
> "Fu, Yuan" <ykf5041@psu.edu> writes:
> 
>> In Emacs 27, doc-view doesn’t to image rescaling if imagemagick is not
>> present.  However, since we have native image rescaling now, we want
>> to rescale regardless of imagemagick. I also added convenient
>> centering commands to doc-view.el. Note that the patch is made on
>> Emacs master branch.
> 
> The imagemagick fixes look good to me, and the new functionality, too.
> But this should probably be done in two separate patches, and the patch
> with the new functionality also needs to be documented in the Document
> View node in the misc.texi manual.  (And it also needs an etc/NEWS
> entry.)
> 
> Can you do the patch splitting and documentation additions and resubmit?
> 

Sure! However, I’ll be busy for a couple months so I need to find time to do it.

Yuan

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Lars Ingebrigtsen]

Yuan Fu <ykf5041@psu.edu> writes:

>> Can you do the patch splitting and documentation additions and resubmit?
>> 
>
> Sure! However, I’ll be busy for a couple months so I need to find time
> to do it.

Great; looking forward to it.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Fu, Yuan]

[-- Attachment #1.1: Type: text/plain, Size: 372 bytes --]



> On Aug 7, 2020, at 3:10 AM, Lars Ingebrigtsen <larsi@gnus.org> wrote:
>
> Yuan Fu <ykf5041@psu.edu> writes:
>
>>> Can you do the patch splitting and documentation additions and resubmit?
>>>
>>
>> Sure! However, I’ll be busy for a couple months so I need to find time
>> to do it.
>
> Great; looking forward to it.

Here is the fix patch:



Yuan

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From e7c62a8a7759f86be189e52c50d780b875ab7853 Mon Sep 17 00:00:00 2001
From: Yuan Fu <casouri@gmail.com>
Date: Thu, 13 Aug 2020 15:03:14 -0400
Subject: [PATCH] Remove imagemagick checks in doc-view.el

The problem with old imagemagick code is that, doc-view checks for
imagemagick and only rescales the image if it is present.  Now that we
have native re-scaling and don't compile with imagemagic by default,
we want to rescale image regardless of imagemagic.

* lisp/doc-view.el (doc-view-mode-p, doc-view-enlarge,
doc-view-scale-reset, doc-view-insert-image): Remove checks for
imagemagick.
---
 lisp/doc-view.el | 17 +++++------------
 1 file changed, 5 insertions(+), 12 deletions(-)

diff --git a/lisp/doc-view.el b/lisp/doc-view.el
index de342f1519..3e2b244326 100644
--- a/lisp/doc-view.el
+++ b/lisp/doc-view.el
@@ -740,8 +740,7 @@ doc-view-mode-p
 Document types are symbols like `dvi', `ps', `pdf', or `odf' (any
 OpenDocument format)."
   (and (display-graphic-p)
-       (or (image-type-available-p 'imagemagick)
-	   (image-type-available-p 'png))
+       (image-type-available-p 'png)
        (cond
 	((eq type 'dvi)
 	 (and (doc-view-mode-p 'pdf)
@@ -769,10 +768,7 @@ doc-view-shrink-factor
 (defun doc-view-enlarge (factor)
   "Enlarge the document by FACTOR."
   (interactive (list doc-view-shrink-factor))
-  (if (and doc-view-scale-internally
-           (eq (plist-get (cdr (doc-view-current-image)) :type)
-               'imagemagick))
-      ;; ImageMagick supports on-the-fly-rescaling.
+  (if doc-view-scale-internally
       (let ((new (ceiling (* factor doc-view-image-width))))
         (unless (equal new doc-view-image-width)
           (setq-local doc-view-image-width new)
@@ -792,9 +788,7 @@ doc-view-shrink
 (defun doc-view-scale-reset ()
   "Reset the document size/zoom level to the initial one."
   (interactive)
-  (if (and doc-view-scale-internally
-           (eq (plist-get (cdr (doc-view-current-image)) :type)
-               'imagemagick))
+  (if doc-view-scale-internally
       (progn
 	(kill-local-variable 'doc-view-image-width)
 	(doc-view-insert-image
@@ -1393,12 +1387,11 @@ doc-view-insert-image
     ;; Only insert the image if the buffer is visible.
     (when (window-live-p (overlay-get ol 'window))
       (let* ((image (if (and file (file-readable-p file))
-			(if (not (and doc-view-scale-internally
-				      (fboundp 'imagemagick-types)))
+			(if (not doc-view-scale-internally)
 			    (apply #'create-image file doc-view--image-type nil args)
 			  (unless (member :width args)
 			    (setq args `(,@args :width ,doc-view-image-width)))
-			  (apply #'create-image file 'imagemagick nil args))))
+			  (apply #'create-image file doc-view--image-type nil args))))
 	     (slice (doc-view-current-slice))
 	     (img-width (and image (car (image-size image))))
 	     (displayed-img-width (if (and image slice)
-- 
2.27.0

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Lars Ingebrigtsen]

"Fu, Yuan" <ykf5041@psu.edu> writes:

> Here is the fix patch:

Thanks; applied to Emacs 28.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Yuan Fu]

[-- Attachment #1: Type: text/plain, Size: 223 bytes --]



> On Aug 14, 2020, at 7:53 AM, Lars Ingebrigtsen <larsi@gnus.org> wrote:
> 
> "Fu, Yuan" <ykf5041@psu.edu> writes:
> 
>> Here is the fix patch:
> 
> Thanks; applied to Emacs 28.

Cool! Here is the centering patch.

Yuan


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From 216f20f3628900c5dc4ea98a14f38b326a71c480 Mon Sep 17 00:00:00 2001
From: Yuan Fu <casouri@gmail.com>
Date: Thu, 13 Aug 2020 15:57:47 -0400
Subject: [PATCH] Add centering commands to doc-view.el

* lisp/doc-view.el (doc-view-mode-map): Add binding for centering
commands.
(doc-view-center-page-horizontally, doc-view-center-page-vertically):
New functions.
---
 lisp/doc-view.el | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/lisp/doc-view.el b/lisp/doc-view.el
index 3e2b244326..77c06a8eaf 100644
--- a/lisp/doc-view.el
+++ b/lisp/doc-view.el
@@ -435,6 +435,9 @@ doc-view-mode-map
     (define-key map (kbd "c m")       'doc-view-set-slice-using-mouse)
     (define-key map (kbd "c b")       'doc-view-set-slice-from-bounding-box)
     (define-key map (kbd "c r")       'doc-view-reset-slice)
+    ;; Centering the image
+    (define-key map (kbd "c h")       'doc-view-center-page-horizontally)
+    (define-key map (kbd "c v")       'doc-view-center-page-vertically)
     ;; Searching
     (define-key map (kbd "C-s")       'doc-view-search)
     (define-key map (kbd "<find>")    'doc-view-search)
@@ -921,6 +924,32 @@ doc-view-fit-window-to-page
     (when new-frame-params
       (modify-frame-parameters (selected-frame) new-frame-params))))
 
+(defun doc-view-center-page-horizontally ()
+  "Center page horizontally when page is wider than window."
+  (interactive)
+  (let ((page-width (car (image-size (doc-view-current-image) 'pixel)))
+        (window-width (window-body-width nil 'pixel))
+        ;; How much do we scroll in order to center the page?
+        (pixel-hscroll 0)
+        ;; How many pixels are there in a column?
+        (col-in-pixel (/ (window-body-width nil 'pixel)
+                         (window-body-width nil))))
+    (when (> page-width window-width)
+      (setq pixel-hscroll (/ (- page-width window-width) 2))
+      (set-window-hscroll (selected-window)
+                          (/ pixel-hscroll col-in-pixel)))))
+
+(defun doc-view-center-page-vertically ()
+  "Center page vertically when page is wider than window."
+  (interactive)
+  (let ((page-height (cdr (image-size (doc-view-current-image) 'pixel)))
+        (window-height (window-body-height nil 'pixel))
+        ;; How much do we scroll in order to center the page?
+        (pixel-scroll 0))
+    (when (> page-height window-height)
+      (setq pixel-scroll (/ (- page-height window-height) 2))
+      (set-window-vscroll (selected-window) pixel-scroll 'pixel))))
+
 (defun doc-view-reconvert-doc ()
   "Reconvert the current document.
 Should be invoked when the cached images aren't up-to-date."
-- 
2.27.0

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Lars Ingebrigtsen]

Yuan Fu <ykf5041@psu.edu> writes:

> Cool! Here is the centering patch.

Thanks; applied to Emacs 28 (with an added NEWS entry).

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#42272: 27.0.91; [PATCH] Fix doc-view rescale

[Yuan Fu]

> On Aug 14, 2020, at 11:43 AM, Lars Ingebrigtsen <larsi@gnus.org> wrote:
> 
> Yuan Fu <ykf5041@psu.edu> writes:

Thank you very much, I forgot about NEWS, sorry.

Yuan