UI: Scrollbar Behavior Changes

Changes to scrollbars so that they are always visible, but thin and
dim, and widen and become more visible as your mouse approaches.

See D6505 for details and examples.

Differential Revision: https://developer.blender.org/D6505

Reviewed by Campbell Barton

1 files changed, 32 insertions, 70 deletions

diff --git a/source/blender/editors/interface/view2d.cc b/source/blender/editors/interface/view2d.cc
index 6ece7eb4ffa..ee4bfd351ae 100644
--- a/source/blender/editors/interface/view2d.cc
+++ b/source/blender/editors/interface/view2d.cc
@@ -149,7 +149,9 @@ static void view2d_masks(View2D *v2d, const rcti *mask_scroll)
     }
   }
 
-  scroll = view2d_scroll_mapped(v2d->scroll);
+  /* Do not use mapped scroll here because we want to update scroller rects
+   * even if they are not displayed.  For init purposes.  See T75003.*/
+  scroll = v2d->scroll;
 
   /* Scrollers are based off region-size:
    * - they can only be on one to two edges of the region they define
@@ -158,7 +160,7 @@ static void view2d_masks(View2D *v2d, const rcti *mask_scroll)
   if (scroll) {
     float scroll_width, scroll_height;
 
-    UI_view2d_scroller_size_get(v2d, &scroll_width, &scroll_height);
+    UI_view2d_scroller_size_get(v2d, false, &scroll_width, &scroll_height);
 
     /* vertical scroller */
     if (scroll & V2D_SCROLL_LEFT) {
@@ -191,18 +193,6 @@ static void view2d_masks(View2D *v2d, const rcti *mask_scroll)
       v2d->hor = *mask_scroll;
       v2d->hor.ymin = v2d->hor.ymax - scroll_height;
     }
-
-    /* adjust vertical scroller if there's a horizontal scroller, to leave corner free */
-    if (scroll & V2D_SCROLL_VERTICAL) {
-      if (scroll & V2D_SCROLL_BOTTOM) {
-        /* on bottom edge of region */
-        v2d->vert.ymin = v2d->hor.ymax;
-      }
-      else if (scroll & V2D_SCROLL_TOP) {
-        /* on upper edge of region */
-        v2d->vert.ymax = v2d->hor.ymin;
-      }
-    }
   }
 }
 
@@ -260,6 +250,7 @@ void UI_view2d_region_reinit(View2D *v2d, short type, int winx, int winy)
       /* tot rect has strictly regulated placement, and must only occur in +/- quadrant */
       v2d->align = (V2D_ALIGN_NO_NEG_X | V2D_ALIGN_NO_POS_Y);
       v2d->keeptot = V2D_KEEPTOT_STRICT;
+      v2d->keepofs = (V2D_KEEPOFS_X | V2D_KEEPOFS_Y);
       tot_changed = do_init;
 
       /* scroller settings are currently not set here... that is left for regions... */
@@ -276,6 +267,7 @@ void UI_view2d_region_reinit(View2D *v2d, short type, int winx, int winy)
       /* tot rect has strictly regulated placement, and must only occur in +/+ quadrant */
       v2d->align = (V2D_ALIGN_NO_NEG_X | V2D_ALIGN_NO_NEG_Y);
       v2d->keeptot = V2D_KEEPTOT_STRICT;
+      v2d->keepofs = (V2D_KEEPOFS_X | V2D_KEEPOFS_Y);
       tot_changed = do_init;
 
       /* scroller settings are currently not set here... that is left for regions... */
@@ -493,8 +485,8 @@ static void ui_view2d_curRect_validate_resize(View2D *v2d, bool resize)
   }
 
   /* check if we should restore aspect ratio (if view size changed) */
-  if (v2d->keepzoom & V2D_KEEPASPECT) {
-    bool do_x = false, do_y = false, do_cur /* , do_win */ /* UNUSED */;
+  if (v2d->keepzoom & V2D_KEEPASPECT && !(v2d->keeptot == V2D_KEEPTOT_STRICT)) {
+    bool do_x = false, do_y = false, do_cur;
     float curRatio, winRatio;
 
     /* when a window edge changes, the aspect ratio can't be used to
@@ -532,53 +524,12 @@ static void ui_view2d_curRect_validate_resize(View2D *v2d, bool resize)
     /* do_win = do_y; */ /* UNUSED */
 
     if (do_cur) {
-      if ((v2d->keeptot == V2D_KEEPTOT_STRICT) && (winx != v2d->oldwinx)) {
-        /* Special exception for Outliner (and later channel-lists):
-         * - The view may be moved left to avoid contents
-         *   being pushed out of view when view shrinks.
-         * - The keeptot code will make sure cur->xmin will not be less than tot->xmin
-         *   (which cannot be allowed).
-         * - width is not adjusted for changed ratios here.
-         */
-        if (winx < v2d->oldwinx) {
-          const float temp = v2d->oldwinx - winx;
-
-          cur->xmin -= temp;
-          cur->xmax -= temp;
-
-          /* width does not get modified, as keepaspect here is just set to make
-           * sure visible area adjusts to changing view shape!
-           */
-        }
-      }
-      else {
-        /* portrait window: correct for x */
-        width = height / winRatio;
-      }
+      /* portrait window: correct for x */
+      width = height / winRatio;
     }
     else {
-      if ((v2d->keeptot == V2D_KEEPTOT_STRICT) && (winy != v2d->oldwiny)) {
-        /* special exception for Outliner (and later channel-lists):
-         * - Currently, no actions need to be taken here...
-         */
-
-        if (winy < v2d->oldwiny) {
-          const float temp = v2d->oldwiny - winy;
-
-          if (v2d->align & V2D_ALIGN_NO_NEG_Y) {
-            cur->ymin -= temp;
-            cur->ymax -= temp;
-          }
-          else { /* Assume V2D_ALIGN_NO_POS_Y or combination */
-            cur->ymin += temp;
-            cur->ymax += temp;
-          }
-        }
-      }
-      else {
-        /* landscape window: correct for y */
-        height = width * winRatio;
-      }
+      /* landscape window: correct for y */
+      height = width * winRatio;
     }
 
     /* store region size for next time */
@@ -1510,7 +1461,7 @@ void UI_view2d_scrollers_calc(View2D *v2d,
   }
 }
 
-void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
+void UI_view2d_scrollers_draw_ex(View2D *v2d, const rcti *mask_custom, bool use_full_hide)
 {
   View2DScrollers scrollers;
   UI_view2d_scrollers_calc(v2d, mask_custom, &scrollers);
@@ -1518,6 +1469,8 @@ void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
   rcti vert, hor;
   const int scroll = view2d_scroll_mapped(v2d->scroll);
   const char emboss_alpha = btheme->tui.widget_emboss[3];
+  const float alpha_min = use_full_hide ? 0.0f : V2D_SCROLL_MIN_ALPHA;
+
   uchar scrollers_back_color[4];
 
   /* Color for scrollbar backs */
@@ -1530,7 +1483,8 @@ void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
   /* horizontal scrollbar */
   if (scroll & V2D_SCROLL_HORIZONTAL) {
     uiWidgetColors wcol = btheme->tui.wcol_scroll;
-    const float alpha_fac = v2d->alpha_hor / 255.0f;
+    /* 0..255 -> min...1 */
+    const float alpha_fac = ((v2d->alpha_hor / 255.0f) * (1.0f - alpha_min)) + alpha_min;
     rcti slider;
     int state;
 
@@ -1543,8 +1497,8 @@ void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
 
     wcol.inner[3] *= alpha_fac;
     wcol.item[3] *= alpha_fac;
-    wcol.outline[3] *= alpha_fac;
-    btheme->tui.widget_emboss[3] *= alpha_fac; /* will be reset later */
+    wcol.outline[3] = 0;
+    btheme->tui.widget_emboss[3] = 0; /* will be reset later */
 
     /* show zoom handles if:
      * - zooming on x-axis is allowed (no scroll otherwise)
@@ -1565,7 +1519,8 @@ void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
   if (scroll & V2D_SCROLL_VERTICAL) {
     uiWidgetColors wcol = btheme->tui.wcol_scroll;
     rcti slider;
-    const float alpha_fac = v2d->alpha_vert / 255.0f;
+    /* 0..255 -> min...1 */
+    const float alpha_fac = ((v2d->alpha_vert / 255.0f) * (1.0f - alpha_min)) + alpha_min;
     int state;
 
     slider.xmin = vert.xmin;
@@ -1577,8 +1532,8 @@ void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
 
     wcol.inner[3] *= alpha_fac;
     wcol.item[3] *= alpha_fac;
-    wcol.outline[3] *= alpha_fac;
-    btheme->tui.widget_emboss[3] *= alpha_fac; /* will be reset later */
+    wcol.outline[3] = 0;
+    btheme->tui.widget_emboss[3] = 0; /* will be reset later */
 
     /* show zoom handles if:
      * - zooming on y-axis is allowed (no scroll otherwise)
@@ -1599,6 +1554,11 @@ void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
   btheme->tui.widget_emboss[3] = emboss_alpha;
 }
 
+void UI_view2d_scrollers_draw(View2D *v2d, const rcti *mask_custom)
+{
+  UI_view2d_scrollers_draw_ex(v2d, mask_custom, false);
+}
+
 /** \} */
 
 /* -------------------------------------------------------------------- */
@@ -1835,13 +1795,14 @@ View2D *UI_view2d_fromcontext_rwin(const bContext *C)
   return &(region->v2d);
 }
 
-void UI_view2d_scroller_size_get(const View2D *v2d, float *r_x, float *r_y)
+void UI_view2d_scroller_size_get(const View2D *v2d, bool mapped, float *r_x, float *r_y)
 {
-  const int scroll = view2d_scroll_mapped(v2d->scroll);
+  const int scroll = (mapped) ? view2d_scroll_mapped(v2d->scroll) : v2d->scroll;
 
   if (r_x) {
     if (scroll & V2D_SCROLL_VERTICAL) {
       *r_x = (scroll & V2D_SCROLL_VERTICAL_HANDLES) ? V2D_SCROLL_HANDLE_WIDTH : V2D_SCROLL_WIDTH;
+      *r_x = ((*r_x - V2D_SCROLL_MIN_WIDTH) * (v2d->alpha_vert / 255.0f)) + V2D_SCROLL_MIN_WIDTH;
     }
     else {
       *r_x = 0;
@@ -1851,6 +1812,7 @@ void UI_view2d_scroller_size_get(const View2D *v2d, float *r_x, float *r_y)
     if (scroll & V2D_SCROLL_HORIZONTAL) {
       *r_y = (scroll & V2D_SCROLL_HORIZONTAL_HANDLES) ? V2D_SCROLL_HANDLE_HEIGHT :
                                                         V2D_SCROLL_HEIGHT;
+      *r_y = ((*r_y - V2D_SCROLL_MIN_WIDTH) * (v2d->alpha_hor / 255.0f)) + V2D_SCROLL_MIN_WIDTH;
     }
     else {
       *r_y = 0;