(setq image-type type)
(if (eq major-mode 'image-mode)
(setq mode-name (format "Image[%s]" type)))
+ (image-transform-check-size)
(if (called-interactively-p 'any)
(message "Repeat this command to go back to displaying the file as text"))))
\f
;; Not yet implemented.
-;;; (defvar image-transform-minor-mode-map
-;;; (let ((map (make-sparse-keymap)))
-;;; ;; (define-key map [(control ?+)] 'image-scale-in)
-;;; ;; (define-key map [(control ?-)] 'image-scale-out)
-;;; ;; (define-key map [(control ?=)] 'image-scale-none)
-;;; ;; (define-key map "c f h" 'image-scale-fit-height)
-;;; ;; (define-key map "c ]" 'image-rotate-right)
-;;; map)
-;;; "Minor mode keymap `image-transform-mode'.")
-;;;
-;;; (define-minor-mode image-transform-mode
-;;; "Minor mode for scaling and rotating images.
-;;; With a prefix argument ARG, enable the mode if ARG is positive,
-;;; and disable it otherwise. If called from Lisp, enable the mode
-;;; if ARG is omitted or nil. This minor mode requires Emacs to have
-;;; been compiled with ImageMagick support."
-;;; nil "image-transform" image-transform-minor-mode-map)
+;; (defvar image-transform-minor-mode-map
+;; (let ((map (make-sparse-keymap)))
+;; ;; (define-key map [(control ?+)] 'image-scale-in)
+;; ;; (define-key map [(control ?-)] 'image-scale-out)
+;; ;; (define-key map [(control ?=)] 'image-scale-none)
+;; ;; (define-key map "c f h" 'image-scale-fit-height)
+;; ;; (define-key map "c ]" 'image-rotate-right)
+;; map)
+;; "Minor mode keymap `image-transform-mode'.")
+;;
+;; (define-minor-mode image-transform-mode
+;; "Minor mode for scaling and rotating images.
+;; With a prefix argument ARG, enable the mode if ARG is positive,
+;; and disable it otherwise. If called from Lisp, enable the mode
+;; if ARG is omitted or nil. This minor mode requires Emacs to have
+;; been compiled with ImageMagick support."
+;; nil "image-transform" image-transform-minor-mode-map)
;; FIXME this doesn't seem mature yet. Document in manual when it is.
- nil, meaning no resizing.
- `fit-height', meaning to fit the image to the window height.
- `fit-width', meaning to fit the image to the window width.
- - A number, which is a scale factor (the default size is 100).")
+ - A number, which is a scale factor (the default size is 1).")
+
+(defvar image-transform-scale 1.0
+ "The scale factor of the image being displayed.")
(defvar image-transform-rotation 0.0
"Rotation angle for the image in the current Image mode buffer.")
+(defvar image-transform-right-angle-fudge 0.0001
+ "Snap distance to a multiple of a right angle.
+There's no deep theory behind the default value, it should just
+be somewhat larger than ImageMagick's MagickEpsilon.")
+
+(defsubst image-transform-width (width height)
+ "Return the bounding box width of a rotated WIDTH x HEIGHT rectangle.
+The rotation angle is the value of `image-transform-rotation' in degrees."
+ (let ((angle (degrees-to-radians image-transform-rotation)))
+ ;; Assume, w.l.o.g., that the vertices of the rectangle have the
+ ;; coordinates (+-w/2, +-h/2) and that (0, 0) is the center of the
+ ;; rotation by the angle A. The projections onto the first axis
+ ;; of the vertices of the rotated rectangle are +- (w/2) cos A +-
+ ;; (h/2) sin A, and the difference between the largest and the
+ ;; smallest of the four values is the expression below.
+ (+ (* width (abs (cos angle))) (* height (abs (sin angle))))))
+
+;; The following comment and code snippet are from
+;; ImageMagick-6.7.4-4/magick/distort.c
+
+;; /* Set the output image geometry to calculated 'bestfit'.
+;; Yes this tends to 'over do' the file image size, ON PURPOSE!
+;; Do not do this for DePolar which needs to be exact for virtual tiling.
+;; */
+;; if ( fix_bounds ) {
+;; geometry.x = (ssize_t) floor(min.x-0.5);
+;; geometry.y = (ssize_t) floor(min.y-0.5);
+;; geometry.width=(size_t) ceil(max.x-geometry.x+0.5);
+;; geometry.height=(size_t) ceil(max.y-geometry.y+0.5);
+;; }
+
+;; Other parts of the same file show that here the origin is in the
+;; left lower corner of the image rectangle, the center of the
+;; rotation is the center of the rectangle and min.x and max.x
+;; (resp. min.y and max.y) are the smallest and the largest of the
+;; projections of the vertices onto the first (resp. second) axis.
+
+(defun image-transform-fit-width (width height length)
+ "Return (w . h) so that a rotated w x h image has exactly width LENGTH.
+The rotation angle is the value of `image-transform-rotation'.
+Write W for WIDTH and H for HEIGHT. Then the w x h rectangle is
+an \"approximately uniformly\" scaled W x H rectangle, which
+currently means that w is one of floor(s W) + {0, 1, -1} and h is
+floor(s H), where s can be recovered as the value of `image-transform-scale'.
+The value of `image-transform-rotation' may be replaced by
+a slightly different angle. Currently this is done for values
+close to a multiple of 90, see `image-transform-right-angle-fudge'."
+ (cond ((< (abs (- (mod (+ image-transform-rotation 90) 180) 90))
+ image-transform-right-angle-fudge)
+ (assert (not (zerop width)) t)
+ (setq image-transform-rotation
+ (float (round image-transform-rotation))
+ image-transform-scale (/ (float length) width))
+ (cons length nil))
+ ((< (abs (- (mod (+ image-transform-rotation 45) 90) 45))
+ image-transform-right-angle-fudge)
+ (assert (not (zerop height)) t)
+ (setq image-transform-rotation
+ (float (round image-transform-rotation))
+ image-transform-scale (/ (float length) height))
+ (cons nil length))
+ (t
+ (assert (not (and (zerop width) (zerop height))) t)
+ (setq image-transform-scale
+ (/ (float (1- length)) (image-transform-width width height)))
+ ;; Assume we have a w x h image and an angle A, and let l =
+ ;; l(w, h) = w |cos A| + h |sin A|, which is the actual width
+ ;; of the bounding box of the rotated image, as calculated by
+ ;; `image-transform-width'. The code snippet quoted above
+ ;; means that ImageMagick puts the rotated image in
+ ;; a bounding box of width L = 2 ceil((w+l+1)/2) - w.
+ ;; Elementary considerations show that this is equivalent to
+ ;; L - w being even and L-3 < l(w, h) <= L-1. In our case, L is
+ ;; the given `length' parameter and our job is to determine
+ ;; reasonable values for w and h which satisfy these
+ ;; conditions.
+ (let ((w (floor (* image-transform-scale width)))
+ (h (floor (* image-transform-scale height))))
+ ;; Let w and h as bound above. Then l(w, h) <= l(s W, s H)
+ ;; = L-1 < l(w+1, h+1) = l(w, h) + l(1, 1) <= l(w, h) + 2,
+ ;; hence l(w, h) > (L-1) - 2 = L-3.
+ (cons
+ (cond ((= (mod w 2) (mod length 2))
+ w)
+ ;; l(w+1, h) >= l(w, h) > L-3, but does l(w+1, h) <=
+ ;; L-1 hold?
+ ((<= (image-transform-width (1+ w) h) (1- length))
+ (1+ w))
+ ;; No, it doesn't, but this implies that l(w-1, h) =
+ ;; l(w+1, h) - l(2, 0) >= l(w+1, h) - 2 > (L-1) -
+ ;; 2 = L-3. Clearly, l(w-1, h) <= l(w, h) <= L-1.
+ (t
+ (1- w)))
+ h)))))
+
+(defun image-transform-check-size ()
+ "Check that the image exactly fits the width/height of the window."
+ (unless (numberp image-transform-resize)
+ (let ((size (image-display-size (image-get-display-property) t)))
+ (cond ((eq image-transform-resize 'fit-width)
+ (assert (= (car size)
+ (- (nth 2 (window-inside-pixel-edges))
+ (nth 0 (window-inside-pixel-edges))))
+ t))
+ ((eq image-transform-resize 'fit-height)
+ (assert (= (cdr size)
+ (- (nth 3 (window-inside-pixel-edges))
+ (nth 1 (window-inside-pixel-edges))))
+ t))))))
+
(defun image-transform-properties (spec)
"Return rescaling/rotation properties for image SPEC.
These properties are determined by the Image mode variables
Rescaling and rotation properties only take effect if Emacs is
compiled with ImageMagick support."
+ (setq image-transform-scale 1.0)
(when (or image-transform-resize
- (not (equal image-transform-rotation 0.0)))
+ (/= image-transform-rotation 0.0))
;; Note: `image-size' looks up and thus caches the untransformed
;; image. There's no easy way to prevent that.
(let* ((size (image-size spec t))
- (height
+ (resized
(cond
((numberp image-transform-resize)
- (unless (= image-transform-resize 100)
- (* image-transform-resize (cdr size))))
+ (unless (= image-transform-resize 1)
+ (setq image-transform-scale image-transform-resize)
+ (cons nil (floor (* image-transform-resize (cdr size))))))
+ ((eq image-transform-resize 'fit-width)
+ (image-transform-fit-width
+ (car size) (cdr size)
+ (- (nth 2 (window-inside-pixel-edges))
+ (nth 0 (window-inside-pixel-edges)))))
((eq image-transform-resize 'fit-height)
- (- (nth 3 (window-inside-pixel-edges))
- (nth 1 (window-inside-pixel-edges))))))
- (width (if (eq image-transform-resize 'fit-width)
- (- (nth 2 (window-inside-pixel-edges))
- (nth 0 (window-inside-pixel-edges))))))
- ;;TODO fit-to-* should consider the rotation angle
- `(,@(if height (list :height height))
- ,@(if width (list :width width))
- ,@(if (not (equal 0.0 image-transform-rotation))
- (list :rotation image-transform-rotation))))))
-
-;; FIXME 2 works, but eg 1.9 or 0.5 don't?
+ (let ((res (image-transform-fit-width
+ (cdr size) (car size)
+ (- (nth 3 (window-inside-pixel-edges))
+ (nth 1 (window-inside-pixel-edges))))))
+ (cons (cdr res) (car res)))))))
+ `(,@(when (car resized)
+ (list :width (car resized)))
+ ,@(when (cdr resized)
+ (list :height (cdr resized)))
+ ,@(unless (= 0.0 image-transform-rotation)
+ (list :rotation image-transform-rotation))))))
+
(defun image-transform-set-scale (scale)
"Prompt for a number, and resize the current image by that amount.
This command has no effect unless Emacs is compiled with
ROTATION should be in degrees. This command has no effect unless
Emacs is compiled with ImageMagick support."
(interactive "nRotation angle (in degrees): ")
- ;;TODO 0 90 180 270 degrees are the only reasonable angles here
- ;;otherwise combining with rescaling will get very awkward
- (setq image-transform-rotation (float rotation))
+ (setq image-transform-rotation (float (mod rotation 360)))
(image-toggle-display-image))
(provide 'image-mode)