Files
cl-tty/src/components/scrollbox.lisp

96 lines
4.6 KiB
Common Lisp

(in-package #:cl-tty.container)
(defclass scroll-box (dirty-mixin)
((children :initform nil :initarg :children :accessor scroll-box-children :type list)
(scroll-y :initform 0 :initarg :scroll-y :accessor scroll-box-scroll-y :type fixnum)
(scroll-x :initform 0 :initarg :scroll-x :accessor scroll-box-scroll-x :type fixnum)
(sticky-scroll-p :initform t :initarg :sticky-scroll-p :accessor sticky-scroll-p :type boolean)
(layout-node :initform (make-layout-node) :accessor scroll-box-layout-node)))
(defun make-scroll-box (&key (children nil) (scroll-y 0) (scroll-x 0) sticky-scroll-p)
(make-instance 'scroll-box
:children children :scroll-y scroll-y :scroll-x scroll-x
:sticky-scroll-p (if (null sticky-scroll-p) t sticky-scroll-p)))
(defmethod component-children ((sb scroll-box)) (scroll-box-children sb))
(defmethod component-layout-node ((sb scroll-box)) (scroll-box-layout-node sb))
(defun clamp-scroll (sb)
(let* ((ln (scroll-box-layout-node sb))
(viewport-h (if ln (layout-node-height ln) 0))
(viewport-w (if ln (layout-node-width ln) 0))
(content-h (scroll-box-content-height sb))
(content-w (scroll-box-content-width sb)))
(setf (scroll-box-scroll-y sb) (max 0 (min (scroll-box-scroll-y sb) (- content-h viewport-h))))
(setf (scroll-box-scroll-x sb) (max 0 (min (scroll-box-scroll-x sb) (- content-w viewport-w))))))
(defun scroll-by (sb dy dx)
(incf (scroll-box-scroll-y sb) dy) (incf (scroll-box-scroll-x sb) dx)
(clamp-scroll sb) (mark-dirty sb))
(defun scroll-box-content-height (sb)
(reduce #'+ (scroll-box-children sb)
:key (lambda (c) (let ((ln (component-layout-node c))) (if ln (max 1 (layout-node-height ln)) 1)))
:initial-value 0))
(defun scroll-box-content-width (sb)
(reduce #'max (scroll-box-children sb)
:key (lambda (c) (let ((ln (component-layout-node c))) (if ln (max 1 (layout-node-width ln)) 1)))
:initial-value 0))
(defmethod render ((sb scroll-box) backend)
"Render ScrollBox children within the viewport, offset by scroll position.
Children outside the viewport are skipped."
(let* ((ln (scroll-box-layout-node sb))
(vx 0) (vy 0)
(vw (if ln (layout-node-width ln) 80))
(vh (if ln (layout-node-height ln) 24))
(sy (scroll-box-scroll-y sb))
(sx (scroll-box-scroll-x sb)))
(declare (ignore vx))
(dolist (child (scroll-box-children sb))
(let* ((cln (component-layout-node child))
(ch (if cln (layout-node-height cln) 1))
(cy vy))
;; Only render children that are visible in the viewport
(when (and (< (+ cy (- sy)) (+ vh vy))
(> (+ cy (- sy) ch) vy))
;; Temporarily offset child's layout-node position for rendering
(let ((orig-x (if cln (layout-node-x cln) 0))
(orig-y (if cln (layout-node-y cln) 0)))
(when cln
(setf (layout-node-x cln) (- orig-x sx)
(layout-node-y cln) (- orig-y sy)))
(unwind-protect
(render child backend)
(when cln
(setf (layout-node-x cln) orig-x
(layout-node-y cln) orig-y)))))
(incf vy ch)))
(draw-scrollbars sb backend vw vh)))
(defun scrollbar-thumb (scroll-pos viewport-size content-size)
(if (> content-size viewport-size) (/ (float scroll-pos) (- content-size viewport-size)) 0.0))
(defun draw-scrollbars (sb backend viewport-w viewport-h)
(let* ((content-h (scroll-box-content-height sb)) (content-w (scroll-box-content-width sb))
(sy (scroll-box-scroll-y sb)) (sx (scroll-box-scroll-x sb)))
(when (> content-h viewport-h)
(let* ((thumb (scrollbar-thumb sy viewport-h content-h))
(thumb-pos (round (* thumb viewport-h))))
(draw-rect backend (1- viewport-w) 0 1 viewport-h :bg :bright-black)
(draw-text backend (1- viewport-w) thumb-pos "█" nil nil)))
(when (> content-w viewport-w)
(let* ((thumb (scrollbar-thumb sx viewport-w content-w))
(thumb-pos (round (* thumb viewport-w))))
(draw-rect backend 0 (1- viewport-h) viewport-w 1 :bg :bright-black)
(draw-text backend thumb-pos (1- viewport-h) "█" nil nil)))))
(defun update-sticky-scroll (sb)
(when (sticky-scroll-p sb)
(let* ((content-h (scroll-box-content-height sb))
(ln (scroll-box-layout-node sb))
(viewport-h (if ln (layout-node-height ln) 24)))
(when (>= (scroll-box-scroll-y sb) (- content-h viewport-h 1))
(setf (scroll-box-scroll-y sb) (max 0 (- content-h viewport-h)))))))