Adds brush color alpha hotkey

frontend/src/features/canvas/components/IAICanvasToolbar/IAICanvasToolChooserOptions.tsx

@@ -86,7 +86,7 @@ const IAICanvasToolChooserOptions = () => {
   );
 
   useHotkeys(
-    ['['],
+    ['BracketLeft'],
     () => {
       dispatch(setBrushSize(Math.max(brushSize - 5, 5)));
     },
@@ -98,7 +98,7 @@ const IAICanvasToolChooserOptions = () => {
   );
 
   useHotkeys(
-    [']'],
+    ['BracketRight'],
     () => {
       dispatch(setBrushSize(Math.min(brushSize + 5, 500)));
     },
@@ -109,6 +109,40 @@ const IAICanvasToolChooserOptions = () => {
     [brushSize]
   );
 
+  useHotkeys(
+    ['shift+BracketLeft'],
+    () => {
+      dispatch(
+        setBrushColor({
+          ...brushColor,
+          a: _.clamp(brushColor.a - 0.05, 0.05, 1),
+        })
+      );
+    },
+    {
+      enabled: () => true,
+      preventDefault: true,
+    },
+    [brushColor]
+  );
+
+  useHotkeys(
+    ['shift+BracketRight'],
+    () => {
+      dispatch(
+        setBrushColor({
+          ...brushColor,
+          a: _.clamp(brushColor.a + 0.05, 0.05, 1),
+        })
+      );
+    },
+    {
+      enabled: () => true,
+      preventDefault: true,
+    },
+    [brushColor]
+  );
+
   const handleSelectBrushTool = () => dispatch(setTool('brush'));
   const handleSelectEraserTool = () => dispatch(setTool('eraser'));
   const handleSelectColorPickerTool = () => dispatch(setTool('colorPicker'));

frontend/src/features/system/components/HotkeysModal/HotkeysModal.tsx

@@ -158,6 +158,16 @@ export default function HotkeysModal({ children }: HotkeysModalProps) {
       desc: 'Increases the size of the canvas brush/eraser',
       hotkey: ']',
     },
+    {
+      title: 'Decrease Brush Opacity',
+      desc: 'Decreases the opacity of the canvas brush',
+      hotkey: 'Shift + [',
+    },
+    {
+      title: 'Increase Brush Opacity',
+      desc: 'Increases the opacity of the canvas brush',
+      hotkey: 'Shift + ]',
+    },
     {
       title: 'Move Tool',
       desc: 'Allows canvas navigation',