Add scrollable

scrollable, scroll and scrollSpeed attributes addded to Node, and corresponding setters

minimal_scroll.nim added in examples

Author: alt-tosc

examples/minimal_scroll/minimal_scroll.nim

@@ -0,0 +1,21 @@
+## This minimal example shows 5 blue squares in a scroll box
+
+import fidget
+
+proc drawMain() =
+  frame "main":
+    box 0, 0, 620, 140
+    frame "scrollBox":
+      box 5, 5, 610, 130
+      stroke "#000"
+      strokeWeight 1
+      clipContent true
+      scrollable true
+      fill "#FFF"
+      for i in 0 .. 4:
+        group "blockA" & $i:
+          scrollSpeed (i + 1) * 2 - 6
+          box 15 + (float i) * 120, 15, 100, 100
+          fill "#2B9FEA"
+
+startFidget(drawMain, w = 620, h = 140)

src/fidget.nim

@@ -280,6 +280,11 @@ proc box*(x, y, w, h: float32) =
   current.box.w = w
   current.box.h = h
 
+  ## Apply scrolling
+  if not parent.isNil:
+    if parent.scrollable:
+      current.box.y += parent.scroll.y * current.scrollSpeed
+
 proc box*(
   x: int|float32|float64,
   y: int|float32|float64,
@@ -358,6 +363,23 @@ proc scrollBars*(scrollBars: bool) =
   ## Causes the parent to clip the children and draw scroll bars.
   current.scrollBars = scrollBars
 
+proc scrollable*(scrollable: bool) =
+  ## Causes the parent to let scroll its children.
+  current.scrollable = scrollable
+
+  ## Accumulate scroll value
+  if current.scrollable:
+    onHover:
+      current.scroll.y += mouse.wheelDelta
+
+proc scrollSpeed*(scrollSpeed: float) =
+  ## Sets the speed at which a child is scolled inside its parent's box
+  current.scrollSpeed = scrollSpeed
+
+proc scrollSpeed*(scrollSpeed: int) =
+  ## Sets the speed at which a child is scolled inside its parent's box
+  current.scrollSpeed = float scrollSpeed
+
 proc cursorColor*(color: Color) =
   ## Sets the color of the text cursor.
   current.cursorColor = color

src/fidget/common.nim

@@ -142,6 +142,9 @@ type
     textLayoutWidth*: float32
     ## Can the text be selected.
     selectable*: bool
+    scrollable*: bool
+    scroll*: Vec2
+    scrollSpeed*: float
     scrollBars*: bool ## Should it have scroll bars if children are clipped.
 
   KeyState* = enum
@@ -320,6 +323,7 @@ proc resetToDefault*(node: Node)=
   node.clipContent = false
   node.diffIndex = 0
   node.selectable = false
+  node.scrollSpeed = 1
 
 proc setupRoot*() =
   if root == nil: