UI: New button/widget type for Asset Browser like preview tiles

This button type shows a preview image above centered text, similar to
the File Browser files in Thumbnail Display Mode or the default Asset
Browser display. In fact we may want to port these over to use the new
button type at some point.

Will be used by the asset view UI template that will be added in a
following commit. That is basically a mini version of the Asset Browser
that can be displayed elsewhere in the UI.

1 files changed, 56 insertions, 17 deletions

diff --git a/source/blender/editors/interface/interface_widgets.c b/source/blender/editors/interface/interface_widgets.c
index 8abff4ad0d8..bcd945b21a9 100644
--- a/source/blender/editors/interface/interface_widgets.c
+++ b/source/blender/editors/interface/interface_widgets.c
@@ -105,6 +105,7 @@ typedef enum {
   /* specials */
   UI_WTYPE_ICON,
   UI_WTYPE_ICON_LABEL,
+  UI_WTYPE_PREVIEW_TILE,
   UI_WTYPE_SWATCH,
   UI_WTYPE_RGB_PICKER,
   UI_WTYPE_UNITVEC,
@@ -4018,6 +4019,14 @@ static void widget_textbut(uiWidgetColors *wcol, rcti *rect, int state, int roun
   widgetbase_draw(&wtb, wcol);
 }
 
+static void widget_preview_tile(
+    uiBut *but, uiWidgetColors *wcol, rcti *rect, int UNUSED(state), int UNUSED(roundboxalign))
+{
+  const uiStyle *style = UI_style_get();
+  ui_draw_preview_item_stateless(
+      &style->widget, rect, but->drawstr, but->icon, wcol->text, UI_STYLE_TEXT_CENTER);
+}
+
 static void widget_menuiconbut(uiWidgetColors *wcol,
                                rcti *rect,
                                int UNUSED(state),
@@ -4483,6 +4492,13 @@ static uiWidgetType *widget_type(uiWidgetTypeEnum type)
       wt.custom = widget_icon_has_anim;
       break;
 
+    case UI_WTYPE_PREVIEW_TILE:
+      wt.draw = NULL;
+      /* Drawn via the `custom` callback. */
+      wt.text = NULL;
+      wt.custom = widget_preview_tile;
+      break;
+
     case UI_WTYPE_SWATCH:
       wt.custom = widget_swatch;
       break;
@@ -4778,6 +4794,10 @@ void ui_draw_but(const bContext *C, struct ARegion *region, uiStyle *style, uiBu
         wt = widget_type(UI_WTYPE_BOX);
         break;
 
+      case UI_BTYPE_PREVIEW_TILE:
+        wt = widget_type(UI_WTYPE_PREVIEW_TILE);
+        break;
+
       case UI_BTYPE_EXTRA:
         widget_draw_extra_mask(C, but, widget_type(UI_WTYPE_BOX), rect);
         break;
@@ -4931,13 +4951,15 @@ void ui_draw_but(const bContext *C, struct ARegion *region, uiStyle *style, uiBu
     wt->draw(&wt->wcol, rect, state, roundboxalign);
   }
 
-  if (use_alpha_blend) {
-    GPU_blend(GPU_BLEND_ALPHA);
-  }
+  if (wt->text) {
+    if (use_alpha_blend) {
+      GPU_blend(GPU_BLEND_ALPHA);
+    }
 
-  wt->text(fstyle, &wt->wcol, but, rect);
-  if (use_alpha_blend) {
-    GPU_blend(GPU_BLEND_NONE);
+    wt->text(fstyle, &wt->wcol, but, rect);
+    if (use_alpha_blend) {
+      GPU_blend(GPU_BLEND_NONE);
+    }
   }
 }
 
@@ -5459,17 +5481,20 @@ void ui_draw_menu_item(const uiFontStyle *fstyle,
   }
 }
 
-void ui_draw_preview_item(
-    const uiFontStyle *fstyle, rcti *rect, const char *name, int iconid, int state)
+/**
+ * Version of #ui_draw_preview_item() that does not draw the menu background and item text based on
+ * state. It just draws the preview and text directly.
+ */
+void ui_draw_preview_item_stateless(const uiFontStyle *fstyle,
+                                    rcti *rect,
+                                    const char *name,
+                                    int iconid,
+                                    const uchar text_col[4],
+                                    eFontStyle_Align text_align)
 {
   rcti trect = *rect;
   const float text_size = UI_UNIT_Y;
   float font_dims[2] = {0.0f, 0.0f};
-  uiWidgetType *wt = widget_type(UI_WTYPE_MENU_ITEM);
-
-  /* drawing button background */
-  wt->state(wt, state, 0, UI_EMBOSS_UNDEFINED);
-  wt->draw(&wt->wcol, rect, 0, 0);
 
   /* draw icon in rect above the space reserved for the label */
   rect->ymin += text_size;
@@ -5481,8 +5506,6 @@ void ui_draw_preview_item(
       fstyle->uifont_id, name, BLF_DRAW_STR_DUMMY_MAX, &font_dims[0], &font_dims[1]);
 
   /* text rect */
-  trect.xmin += 0;
-  trect.xmax = trect.xmin + font_dims[0] + U.widget_unit / 2;
   trect.ymin += U.widget_unit / 2;
   trect.ymax = trect.ymin + font_dims[1];
   if (trect.xmax > rect->xmax - PREVIEW_PAD) {
@@ -5501,11 +5524,27 @@ void ui_draw_preview_item(
     UI_fontstyle_draw(fstyle,
                       &trect,
                       drawstr,
-                      wt->wcol.text,
+                      text_col,
                       &(struct uiFontStyleDraw_Params){
-                          .align = UI_STYLE_TEXT_CENTER,
+                          .align = text_align,
                       });
   }
 }
 
+void ui_draw_preview_item(const uiFontStyle *fstyle,
+                          rcti *rect,
+                          const char *name,
+                          int iconid,
+                          int state,
+                          eFontStyle_Align text_align)
+{
+  uiWidgetType *wt = widget_type(UI_WTYPE_MENU_ITEM);
+
+  /* drawing button background */
+  wt->state(wt, state, 0, UI_EMBOSS_UNDEFINED);
+  wt->draw(&wt->wcol, rect, 0, 0);
+
+  ui_draw_preview_item_stateless(fstyle, rect, name, iconid, wt->wcol.text, text_align);
+}
+
 /** \} */