From c2bc9d939aa1b4cdd5f00e72df30f4f122e933ed Mon Sep 17 00:00:00 2001
From: Henrik Danielsson <h.danielsson@gmail.com>
Date: Mon, 11 Sep 2023 22:58:46 +0200
Subject: [PATCH] Allow setting a solid key background and blending with the
 background.

---
 README.md | 17 +++++++++++++++--
 config.go | 10 ++++++----
 deck.go   | 32 +++++++++++++++++++++++++++++---
 3 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/README.md b/README.md
index c8ac30b..42e2654 100644
--- a/README.md
+++ b/README.md
@@ -371,13 +371,26 @@ pressed:
 
 ### Background Image
 
-You can configure each deck to display an individual wallpaper behind its
-widgets:
+You can configure each deck to display an individual wallpaper behind the entire
+deck:
 
 ```toml
 background = "/some/image.png"
 ```
 
+A key can override the deck background with a solid color:
+
+```toml
+[[keys]]
+  index = 1
+  backgroundColor = "#ff0000" # Sets the background to solid red.
+```
+
+The color is by default rendered on top of any deck background image, but if
+that image has transparency you can also specify `backgroundMode = "blend"` to
+have the background color only show through the transparent image regions.
+This background blend or solid color is static a widget is then rendered on top.
+
 ### Re-using another deck's configuration
 
 If you specify a `parent` inside a deck's configuration, it will inherit all
diff --git a/config.go b/config.go
index e21add0..536bcbb 100644
--- a/config.go
+++ b/config.go
@@ -42,10 +42,12 @@ type WidgetConfig struct {
 
 // KeyConfig holds the entire configuration for a single key.
 type KeyConfig struct {
-	Index      uint8         `toml:"index"`
-	Widget     WidgetConfig  `toml:"widget"`
-	Action     *ActionConfig `toml:"action,omitempty"`
-	ActionHold *ActionConfig `toml:"action_hold,omitempty"`
+	Index           uint8         `toml:"index"`
+	Widget          WidgetConfig  `toml:"widget"`
+	Action          *ActionConfig `toml:"action,omitempty"`
+	ActionHold      *ActionConfig `toml:"action_hold,omitempty"`
+	BackgroundColor string        `toml:"backgroundColor,omitempty"`
+	BackgroundMode  string        `toml:"backgroundMode,omitempty"`
 }
 
 // Keys is a slice of keys.
diff --git a/deck.go b/deck.go
index a260afb..059c0dd 100644
--- a/deck.go
+++ b/deck.go
@@ -3,6 +3,7 @@ package main
 import (
 	"fmt"
 	"image"
+	"image/color"
 	"image/draw"
 	"math"
 	"os"
@@ -20,6 +21,7 @@ import (
 // Deck is a set of widgets.
 type Deck struct {
 	File       string
+	Config     DeckConfig
 	Background image.Image
 	Widgets    []Widget
 }
@@ -38,7 +40,8 @@ func LoadDeck(dev *streamdeck.Device, base string, deck string) (*Deck, error) {
 	}
 
 	d := Deck{
-		File: path,
+		Config: dc,
+		File:   path,
 	}
 	if dc.Background != "" {
 		bgpath, err := expandPath(filepath.Dir(path), dc.Background)
@@ -109,10 +112,33 @@ func (d Deck) backgroundForKey(dev *streamdeck.Device, key uint8) image.Image {
 	pixels := int(dev.Pixels)
 	bg := image.NewRGBA(image.Rect(0, 0, pixels, pixels))
 
-	if d.Background != nil {
+	keyConfig := KeyConfig{}
+	for _, conf := range d.Config.Keys {
+		if conf.Index == key {
+			keyConfig = conf
+			break
+		}
+	}
+	if d.Background != nil || keyConfig.BackgroundColor != "" {
 		startx := int(key%dev.Columns) * (pixels + padding)
 		starty := int(key/dev.Columns) * (pixels + padding)
-		draw.Draw(bg, bg.Bounds(), d.Background, image.Point{startx, starty}, draw.Src)
+		bgDrawn := false
+		if d.Background != nil && keyConfig.BackgroundColor != "" && keyConfig.BackgroundMode != "blend" {
+			draw.Draw(bg, bg.Bounds(), d.Background, image.Point{startx, starty}, draw.Over)
+			bgDrawn = true
+		}
+		if keyConfig.BackgroundColor != "" {
+			var fillColor color.Color
+			err := ConfigValue(keyConfig.BackgroundColor, &fillColor)
+			if err != nil {
+				verbosef("Unabled to parse backgroundColor for key %d", key)
+			} else {
+				draw.Draw(bg, bg.Bounds(), &image.Uniform{fillColor}, image.Point{startx, starty}, draw.Src)
+			}
+		}
+		if !bgDrawn && d.Background != nil {
+			draw.Draw(bg, bg.Bounds(), d.Background, image.Point{startx, starty}, draw.Over)
+		}
 	}
 
 	return bg