Generate pure-colour images dynamically, instead of reading them

We don't need these PNG files in a directory.

src/UI.py

@@ -1395,11 +1395,10 @@ def init_preview(f):
         borderwidth=0,
         relief="solid",
         )
-    blank = img.png('BEE2/blank')
     pal_picked_fake = [
         ttk.Label(
             frames['preview'],
-            image=blank,
+            image=img.PAL_BG_64,
             )
         for _ in range(32)
         ]
@@ -1507,12 +1506,10 @@ def flow_picker(e=None):
     )
     frmScroll['height'] = height
 
-    # this adds extra blank items on the end to finish the grid nicely.
-    blank_img = img.png('BEE2/blank')
-
+    # This adds extra blank items on the end to finish the grid nicely.
     for i in range(width):
         if i not in pal_items_fake:
-            pal_items_fake.append(ttk.Label(frmScroll, image=blank_img))
+            pal_items_fake.append(ttk.Label(frmScroll, image=img.PAL_BG_64))
         if (num_items % width) <= i < width:  # if this space is empty
             pal_items_fake[i].place(
                 x=((i % width)*65 + 1),
@@ -1535,7 +1532,7 @@ def init_drag_icon():
     drag_win.bind(utils.EVENTS['LEFT_RELEASE'], drag_stop)
     UI['drag_lbl'] = Label(
         drag_win,
-        image=img.png('BEE2/blank'),
+        image=img.PAL_BG_64,
         )
     UI['drag_lbl'].grid(row=0, column=0)
     windows['drag_win'] = drag_win

src/contextWin.py

@@ -15,10 +15,9 @@
 from enum import Enum
 import functools
 import webbrowser
-import itertools
 
 from richTextBox import tkRichText
-import img as png
+import img
 import sound as snd
 import itemPropWin
 import tkMarkdown
@@ -105,7 +104,7 @@ class SPR(Enum):
 def set_sprite(pos, sprite):
     """Set one of the property sprites to a value."""
     widget = wid['sprite', pos]
-    widget['image'] = png.spr(sprite)
+    widget['image'] = img.spr(sprite)
     widget.tooltip_text = SPRITE_TOOL.get(sprite, '')
 
 
@@ -207,7 +206,7 @@ def load_item_data():
 
     for ind, pos in enumerate(SUBITEM_POS[selected_item.num_sub]):
         if pos == -1:
-            wid['subitem', ind]['image'] = png.png('BEE2/alpha_64')
+            wid['subitem', ind]['image'] = img.invis_square(64)
         else:
             wid['subitem', ind]['image'] = selected_item.get_icon(pos)
         wid['subitem', ind]['relief'] = 'flat'
@@ -439,7 +438,7 @@ def init_widgets():
         text="",
         anchor="e",
         compound="left",
-        image=png.spr('gear_ent'),
+        image=img.spr('gear_ent'),
     )
     wid['ent_count'].grid(row=0, column=2, rowspan=2, sticky=E)
     tooltip.add_tooltip(
@@ -457,7 +456,7 @@ def init_widgets():
     for i in range(5):
         wid['subitem', i] = ttk.Label(
             sub_frame,
-            image=png.png('BEE2/alpha_64'),
+            image=img.invis_square(64),
         )
         wid['subitem', i].grid(row=0, column=i)
         utils.bind_leftclick(
@@ -485,7 +484,7 @@ def init_widgets():
     for spr_id in SPR:
         wid['sprite', spr_id] = sprite = ttk.Label(
             spr_frame,
-            image=png.spr('ap_grey'),
+            image=img.spr('ap_grey'),
             relief="raised",
         )
         sprite.grid(row=0, column=spr_id.value)

src/img.py

@@ -10,16 +10,19 @@
 from srctools import Vec
 import utils
 
-from typing import Dict, Tuple
+from typing import Union, Dict, Tuple
 
 LOGGER = utils.getLogger('img')
 
 cached_img = {}  # type: Dict[Tuple[str, int], ImageTk.PhotoImage]
 # r, g, b, size -> image
-cached_squares = {}  # type: Dict[Tuple[float, float, float, int], ImageTk.PhotoImage]
+cached_squares = {}  # type: Dict[Union[Tuple[float, float, float, int], Tuple[str, int]], ImageTk.PhotoImage]
 
+# Colour of the palette item background
+PETI_ITEM_BG = Vec(229, 232, 233)
 
-def png(path, resize_to=None, error=None, algo=Image.NEAREST):
+
+def png(path, resize_to=0, error=None, algo=Image.NEAREST):
     """Loads in an image for use in TKinter.
 
     - The .png suffix will automatically be added.
@@ -35,7 +38,7 @@ def png(path, resize_to=None, error=None, algo=Image.NEAREST):
     orig_path = path
 
     try:
-        return cached_img[orig_path, resize_to]
+        return cached_img[path, resize_to]
     except KeyError:
         pass
 
@@ -106,10 +109,30 @@ def color_square(color: Vec, size=16):
             color=(int(color.x), int(color.y), int(color.z)),
         )
         tk_img = ImageTk.PhotoImage(image=img)
-        cached_squares[color.as_tuple(), size] = tk_img
+        cached_squares[key] = tk_img
+
+
+def invis_square(size):
+    """Create a square image of the given size, filled with 0-alpha pixels."""
+
+    try:
+        return cached_squares['alpha', size]
+    except KeyError:
+        img = Image.new(
+            mode='RGBA',
+            size=(size, size),
+            color=(0, 0, 0, 0),
+        )
+        tk_img = ImageTk.PhotoImage(image=img)
+        cached_squares['alpha', size] = tk_img
 
         return tk_img
 
+BLACK_64 = color_square(Vec(0, 0, 0), size=64)
+BLACK_96 = color_square(Vec(0, 0, 0), size=96)
+PAL_BG_64 = color_square(PETI_ITEM_BG, size=64)
+PAL_BG_96 = color_square(PETI_ITEM_BG, size=96)
 
 # If image is not readable, use this instead
-img_error = png('BEE2/error')
+# If this actually fails, use the black image.
+img_error = png('BEE2/error', error=BLACK_64)

src/selectorWin.py

@@ -269,12 +269,16 @@ def __init__(
         else:
             self.context_lbl = self.longName
         if icon is None:
-            self.icon = img.png(
-                'BEE2/blank_96',
-                error=err_icon,
-                resize_to=ICON_SIZE,
+            self.icon = img.color_square(
+                img.PETI_ITEM_BG,
+                ICON_SIZE,
+            )
+            self.ico_file = None
+        elif icon == '<black>':
+            self.icon = img.color_square(
+                Vec(),
+                ICON_SIZE,
             )
-            self.ico_file = 'BEE2/blank_96'
         else:
             self.icon = img.png(
                 icon,
@@ -547,9 +551,10 @@ def __init__(
         )
         self.prop_icon_frm.grid(row=0, column=0, columnspan=4)
 
-        self.prop_icon = ttk.Label(self.prop_icon_frm)
-        self.prop_icon.img = img.png('BEE2/blank_96')
-        self.prop_icon['image'] = self.prop_icon.img
+        self.prop_icon = ttk.Label(
+            self.prop_icon_frm,
+            image=img.PAL_BG_96,
+        )
         self.prop_icon.grid(row=0, column=0)
 
         name_frame = ttk.Frame(self.prop_frm)