From 1bda71ec3b11eeb4d06c3da094a3cb21bac18d5c Mon Sep 17 00:00:00 2001 From: Tak Kunihiro Date: Fri, 27 Oct 2017 17:17:42 +0300 Subject: [PATCH] Improve pixel-scroll-mode Scroll vertically by number of pixels returned by 'frame-char-height' with or without horizontally scrolled. (Bug#28922) * lisp/pixel-scroll.el (pixel-resolution-fine-flag): When t, scroll by number of pixels returned by 'frame-char-height'. (pixel-scroll-up): Scroll by 'frame-char-height'. Fix algorithm to move cursor to avoid unexpected jump. (pixel-scroll-down): Scroll by 'frame-char-height'. (pixel-bob-at-top-p): Consider number of pixels that is about to scroll. (pixel-posn-y-at-point): Consider existence of an overlay string. Return nil when horizontally scrolled. (pixel-point-at-top-p): Consider number of pixels that is about to scroll. Use different algorithm when horizontally scrolled. (pixel-point-at-bottom-p): Consider number of pixels that is about to scroll. Return nil when horizontally scrolled. (pixel-scroll-pixel-down): Move cursor when horizontally scrolled. (pixel--whistlestop-line-up): Change cosmetics and move cursor when horizontally scrolled. (pixel-line-height): Call 'pixel-visual-line-height' instead of 'line-pixel-height'. (pixel-visual-line-height): New function to return height in pixels of text line where cursor is with or without horizontally scrolled, considering response of display engine. (pixel-visible-pos-in-window): New function to return position of a char shown on text line where cursor is on screen with or without horizontally scrolled. --- lisp/pixel-scroll.el | 188 +++++++++++++++++++++++++++++++------------ 1 file changed, 135 insertions(+), 53 deletions(-) diff --git a/lisp/pixel-scroll.el b/lisp/pixel-scroll.el index 4f183addaa0..2213a0239db 100644 --- a/lisp/pixel-scroll.el +++ b/lisp/pixel-scroll.el @@ -74,10 +74,13 @@ More wait will result in slow and gentle scroll.") (defvar pixel-resolution-fine-flag nil - "Set scrolling resolution to a pixel instead of a line. -After a pixel scroll, typing C-n or C-p scrolls the window to -make it fully visible, and undoes the effect of the pixel-level -scroll.") + "Set scrolling resolution to pixels instead of a line. +When it is t, scrolling resolution is number of pixels obtained +by `frame-char-height' instead of a line. When it is number, +scrolling resolution is set to number of pixels specified. In +case you need scrolling resolution of a pixel, set to 1. After a +pixel scroll, typing \\[next-line] or \\[previous-line] scrolls the window to make it +fully visible, and undoes the effect of the pixel-level scroll.") ;;;###autoload (define-minor-mode pixel-scroll-mode @@ -102,13 +105,16 @@ This is an alternative of `scroll-up'. Scope moves downward." (interactive) (or arg (setq arg 1)) (dotimes (ii arg) ; move scope downward - (if (pixel-eob-at-top-p) ; when end-of-the-buffer is close - (scroll-up 1) ; relay on robust method - (when (pixel-point-at-top-p) ; prevent too late - (vertical-motion 1)) ; move point downward - (pixel-scroll-pixel-up (if pixel-resolution-fine-flag - 1 - (pixel-line-height)))))) ; move scope downward + (let ((amt (if pixel-resolution-fine-flag + (if (integerp pixel-resolution-fine-flag) + pixel-resolution-fine-flag + (frame-char-height)) + (pixel-line-height)))) + (if (pixel-eob-at-top-p) ; when end-of-the-buffer is close + (scroll-up 1) ; relay on robust method + (while (pixel-point-at-top-p amt) ; prevent too late (multi tries) + (vertical-motion 1)) ; move point downward + (pixel-scroll-pixel-up amt))))) ; move scope downward (defun pixel-scroll-down (&optional arg) "Scroll text of selected window down ARG lines. @@ -116,48 +122,63 @@ This is and alternative of `scroll-down'. Scope moves upward." (interactive) (or arg (setq arg 1)) (dotimes (ii arg) - (if (or (pixel-bob-at-top-p) ; when beginning-of-the-buffer is seen - (pixel-eob-at-top-p)) ; for file with a long line - (scroll-down 1) ; relay on robust method - (while (pixel-point-at-bottom-p) ; prevent too late (multi tries) - (vertical-motion -1)) - (pixel-scroll-pixel-down (if pixel-resolution-fine-flag - 1 - (pixel-line-height -1)))))) - -(defun pixel-bob-at-top-p () - "Return non-nil if beginning of buffer is at top of window." - (equal (window-start) (point-min))) + (let ((amt (if pixel-resolution-fine-flag + (if (integerp pixel-resolution-fine-flag) + pixel-resolution-fine-flag + (frame-char-height)) + (pixel-line-height -1)))) + (if (or (pixel-bob-at-top-p amt) ; when beginning-of-the-buffer is seen + (pixel-eob-at-top-p)) ; for file with a long line + (scroll-down 1) ; relay on robust method + (while (pixel-point-at-bottom-p amt) ; prevent too late (multi tries) + (vertical-motion -1)) + (pixel-scroll-pixel-down amt))))) + +(defun pixel-bob-at-top-p (amt) + "Return non-nil if window-start is at beginning of the current buffer. +Window must be vertically scrolled by not more than AMT pixels." + (and (equal (window-start) (point-min)) + (< (window-vscroll nil t) amt))) (defun pixel-eob-at-top-p () "Return non-nil if end of buffer is at top of window." (<= (count-lines (window-start) (window-end)) 2)) ; count-screen-lines (defun pixel-posn-y-at-point () - "Return y coordinates of point in pixels of current window." - (let ((hscroll0 (window-hscroll)) - (y (cdr (posn-x-y (posn-at-point))))) - ;; when point is out of scope by hscroll - (unless y - (save-excursion - (set-window-hscroll nil (current-column)) - (setq y (cdr (posn-x-y (posn-at-point)))) - (set-window-hscroll nil hscroll0))) - y)) - -(defun pixel-point-at-top-p () - "Return if point is located at top of a window." - (let* ((y (pixel-posn-y-at-point)) - (top-margin y)) - (< top-margin (pixel-line-height)))) - -(defun pixel-point-at-bottom-p () - "Return if point is located at bottom of a window." - (let* ((y (pixel-posn-y-at-point)) - (edges (window-inside-pixel-edges)) + "Return y coordinates of point in pixels of current window. +This returns nil when horizontally scrolled." + (when (equal (window-hscroll) 0) + (save-excursion + ;; When there's an overlay string on a line, move + ;; point by (beginning-of-visual-line). + (beginning-of-visual-line) + ;; (- (cadr (pos-visible-in-window-p (point) nil t)) + ;; (line-pixel-height)) + (cdr (posn-x-y (posn-at-point)))))) + +(defun pixel-point-at-top-p (amt) + "Return if point is located at top of a window on coming scroll of AMT pixels. +When location of point was not obtained, this returns if point is at top +of window." + (let ((y (pixel-posn-y-at-point)) + top-margin) + (cond + (y + (setq top-margin y) + (< top-margin amt)) + (t + (<= (count-lines (window-start) (point)) 1))))) + +(defun pixel-point-at-bottom-p (amt) + "Return if point is located at bottom of window on coming scroll of AMT pixels. +When location of point was not obtained, this returns nil." + (let* ((edges (window-inside-pixel-edges)) (height (- (nth 3 edges) (nth 1 edges))) ; (- bottom top) - (bottom-margin (- height (+ y (line-pixel-height))))) ; bottom margin - (< bottom-margin (pixel-line-height -1)))) ; coming unseen line + (y (pixel-posn-y-at-point)) + bottom-margin) + (when y + (setq bottom-margin (- height (+ y (pixel-visual-line-height)))) + (< bottom-margin amt)))) ; coming unseen line (defun pixel-scroll-pixel-up (amt) "Scroll text of selected windows up AMT pixels. @@ -173,8 +194,12 @@ Scope moves upward." (while (> amt 0) (let ((vs (window-vscroll nil t))) (if (equal vs 0) - (pixel-scroll-down-and-set-window-vscroll - (1- (pixel-line-height -1))) + (progn + ;; On horizontal scrolling, move cursor. + (when (> (window-hscroll) 0) + (vertical-motion -1)) + (pixel-scroll-down-and-set-window-vscroll + (1- (pixel-line-height -1)))) (set-window-vscroll nil (1- vs) t)) (setq amt (1- amt)) (sit-for pixel-wait)))) @@ -189,11 +214,16 @@ Scope moves downward. This function returns number of pixels that was scrolled." (let* ((src (window-vscroll nil t)) ; EXAMPLE (initial) @0 @8 @88 (height (pixel-line-height)) ; 25 25 23 - (line (1+ (/ src height))) ; catch up + one line Ä1 Ä1 Ä4 + (line (1+ (/ src height))) ; catch up + one line 1 1 4 (dst (* line height)) ; goal @25 @25 @92 (delta (- dst src))) ; pixels to be scrolled 25 17 4 (pixel--whistlestop-pixel-up (1- delta)) ; until one less @24 @24 @91 - (scroll-up line) (sit-for pixel-wait) ; scroll 1 pixel @0 @0 @0 + (dotimes (ii line) + ;; On horizontal scrolling, move cursor. + (when (> (window-hscroll) 0) + (vertical-motion 1)) + (scroll-up 1)) + (sit-for pixel-wait) ; scroll 1 pixel @0 @0 @0 delta)) (defun pixel--whistlestop-pixel-up (n) @@ -211,9 +241,61 @@ unseen line above the first line, respectively, is provided." (or pos (setq pos (window-start))) (when (< pos 0) (setq pos (pixel-point-at-unseen-line))) - (save-excursion - (goto-char pos) - (line-pixel-height))) ; frame-char-height + (let ((vs1 (window-vscroll nil t)) + height) + (set-window-vscroll nil 0 t) + (save-excursion + (goto-char pos) + (setq height (pixel-visual-line-height))) ; line-pixel-height, frame-char-height + (set-window-vscroll nil vs1 t) + height)) + +(defun pixel-visual-line-height () + "Return height in pixels of text line where cursor is in the selected window." + (let ((pos (pixel-visible-pos-in-window))) + (cond + ;; When a char of line is shown, obtain height by + ;; (line-pixel-height). + (pos (save-excursion (goto-char pos) (line-pixel-height))) + ;; When no char of line is shown but the line is at the top, + ;; obtain height by (line-pixel-height). This is based on + ;; expected response from display engine. See following + ;; discussion. + ;; https://lists.gnu.org/archive/html/emacs-devel/2017-10/msg00621.html + ((equal (count-lines (window-start) (point)) 1) + (line-pixel-height)) + ;; No char of line is shown and the line is not at the top, + ;; obtain height by (frame-char-height). + (t (frame-char-height))))) + +(defun pixel-visible-pos-in-window () + "Return position shown on text line where cursor is in the selected window. +This will look for positions of point and end-of-visual-line, +then positions from beginning-of-visual-line to +end-of-visual-line. When no char in a line is shown, this +returns nil." + (let* ((beginning-of-visual-line-pos (save-excursion (beginning-of-visual-line) (point))) + (end-of-visual-line-pos (save-excursion (end-of-visual-line) (point))) + (pos-list (number-sequence beginning-of-visual-line-pos end-of-visual-line-pos)) + (edges (window-inside-pixel-edges)) + (width (- (nth 2 edges) (nth 0 edges))) + posn-x + visible-pos) + ;; Optimize list of position to be surveyed. + (push end-of-visual-line-pos pos-list) + (push (point) pos-list) + (delete-dups pos-list) + ;; Find out a char with position X that is more than zero and less + ;; than width of screen. + (while (and (not visible-pos) + pos-list) + (setq posn-x (car (pos-visible-in-window-p (car pos-list) nil t))) + (if (and posn-x + (<= 0 posn-x) + (< posn-x width)) + (setq visible-pos (car pos-list)) + (setq pos-list (cdr pos-list)))) + visible-pos)) (defun pixel-point-at-unseen-line () "Return the character position of line above the selected window. -- 2.39.2