UI: Draw real node sockets for node input buttons

For buttons representing node inputs (e.g. in the material properties)
rather than drawing some generic socket icon, the actual sockets are
drawn now. That includes color, shape and the selection outline.

This should make it easier to understand what these buttons relate to.

Screenshots: {F8469252}, {F8469248} (The left alignment will be done in
a follow-up commit.)

Differential Revision: https://developer.blender.org/D7409

Reviewed by: Brecht Van Lommel, Clément Foucault, William Reynish

1 files changed, 61 insertions, 21 deletions

diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index ae40b01c77d..53c488bf765 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -42,6 +42,8 @@
 
 #include "BLF_api.h"
 
+#include "ED_node.h"
+
 #include "UI_interface.h"
 #include "UI_interface_icons.h"
 
@@ -2394,6 +2396,30 @@ static void widget_draw_extra_icons(const uiWidgetColors *wcol,
   }
 }
 
+static void widget_draw_node_link_socket(const uiWidgetColors *wcol,
+                                         const rcti *rect,
+                                         uiBut *but,
+                                         float alpha)
+{
+  /* Node socket pointer can be passed as custom_data, see UI_but_node_link_set(). */
+  if (but->custom_data) {
+    const float scale = 0.9f / but->block->aspect;
+
+    float col[4];
+    rgba_uchar_to_float(col, but->col);
+    col[3] *= alpha;
+
+    GPU_blend(true);
+    UI_widgetbase_draw_cache_flush();
+    GPU_blend(false);
+
+    ED_node_socket_draw(but->custom_data, rect, col, scale);
+  }
+  else {
+    widget_draw_icon(but, ICON_LAYER_USED, alpha, rect, wcol->text);
+  }
+}
+
 /* draws text and icons for buttons */
 static void widget_draw_text_icon(const uiFontStyle *fstyle,
                                   const uiWidgetColors *wcol,
@@ -2403,15 +2429,27 @@ static void widget_draw_text_icon(const uiFontStyle *fstyle,
   const bool show_menu_icon = ui_but_draw_menu_icon(but);
   float alpha = (float)wcol->text[3] / 255.0f;
   char password_str[UI_MAX_DRAW_STR];
+  bool no_text_padding = false;
 
   ui_but_text_password_hide(password_str, but, false);
 
   /* check for button text label */
   if (ELEM(but->type, UI_BTYPE_MENU, UI_BTYPE_POPOVER) && (but->flag & UI_BUT_NODE_LINK)) {
     rcti temp = *rect;
-    temp.xmin = rect->xmax - BLI_rcti_size_y(rect) - 1;
-    widget_draw_icon(but, ICON_LAYER_USED, alpha, &temp, wcol->text);
-    rect->xmax = temp.xmin;
+    const int size = BLI_rcti_size_y(rect) + 1; /* Not the icon size! */
+
+    if (but->drawflag & UI_BUT_ICON_LEFT) {
+      temp.xmax = rect->xmin + size;
+      rect->xmin = temp.xmax;
+      /* Further padding looks off. */
+      no_text_padding = true;
+    }
+    else {
+      temp.xmin = rect->xmax - size;
+      rect->xmax = temp.xmin;
+    }
+
+    widget_draw_node_link_socket(wcol, &temp, but, alpha);
   }
 
   /* If there's an icon too (made with uiDefIconTextBut) then draw the icon
@@ -2496,28 +2534,30 @@ static void widget_draw_text_icon(const uiFontStyle *fstyle,
     rect->xmin += icon_size + icon_padding;
   }
 
-  int text_padding = (UI_TEXT_MARGIN_X * U.widget_unit) / but->block->aspect;
-  if (but->editstr) {
-    rect->xmin += text_padding;
-  }
-  else if (but->flag & UI_BUT_DRAG_MULTI) {
-    bool text_is_edited = ui_but_drag_multi_edit_get(but) != NULL;
-    if (text_is_edited) {
+  if (!no_text_padding) {
+    int text_padding = (UI_TEXT_MARGIN_X * U.widget_unit) / but->block->aspect;
+    if (but->editstr) {
       rect->xmin += text_padding;
     }
-  }
-  else if (but->drawflag & UI_BUT_TEXT_LEFT) {
-
-    /* Reduce the left padding for labels without an icon. */
-    if ((but->type == UI_BTYPE_LABEL) && !(but->flag & UI_HAS_ICON) &&
-        !ui_block_is_menu(but->block)) {
-      text_padding /= 2;
+    else if (but->flag & UI_BUT_DRAG_MULTI) {
+      bool text_is_edited = ui_but_drag_multi_edit_get(but) != NULL;
+      if (text_is_edited) {
+        rect->xmin += text_padding;
+      }
     }
+    else if (but->drawflag & UI_BUT_TEXT_LEFT) {
 
-    rect->xmin += text_padding;
-  }
-  else if (but->drawflag & UI_BUT_TEXT_RIGHT) {
-    rect->xmax -= text_padding;
+      /* Reduce the left padding for labels without an icon. */
+      if ((but->type == UI_BTYPE_LABEL) && !(but->flag & UI_HAS_ICON) &&
+          !ui_block_is_menu(but->block)) {
+        text_padding /= 2;
+      }
+
+      rect->xmin += text_padding;
+    }
+    else if (but->drawflag & UI_BUT_TEXT_RIGHT) {
+      rect->xmax -= text_padding;
+    }
   }
 
   /* Menu contains sub-menu items with triangle icon on their right. Shortcut