feat(build): automate legacy *.icns icon creation (#10)

Icons/Exports/README.md

@@ -1,27 +1,11 @@
-# EmacsLG Legacy *.icns Exports
+# EmacsLG PNG Exports
 
-We have a `EmacsLG-Iconsets.afdesign` Affinity Designer document which contains
-high-res versions of all icon variants, and export configurations to export all
-icons at all required sizes to relevant `*.iconset` folders.
+PNG images here are exported from Icon Composer at 1024x1024@2x, meaning they're
+actually 2048x2048 at 144 DPI.
 
-I picked Affinity Designer cause I'm familiar with its export features.
+The `*-iOS-*` files are confusingly, for iOS and macOS Liquid Glass icon
+creation.
 
-## Exporting *.iconset directories
-
-Within Affinity Designer, simply switch to the Export persona, and click the
-"Export Slices" button. This will create all `*.iconset` directories with all
-resolutions of images.
-
-## Create *.icns files
-
-The `*.icns` icon files are creates from the `*.iconset` directories using the
-`iconutil` CLI tool:
-
-```bash
-iconutil -c icns 'EmacsLG1-Default.iconset'
-iconutil -c icns 'EmacsLG1-Dark.iconset'
-iconutil -c icns 'EmacsLG2-Default.iconset'
-iconutil -c icns 'EmacsLG2-Dark.iconset'
-iconutil -c icns 'EmacsLG3-Default.iconset'
-iconutil -c icns 'EmacsLG3-Dark.iconset'
-```
+The `*-macOS-*` files are exported with Icon Composers' export platform set to
+"macOS pre-Tahoe". This effectively adds a transparent padding around the icon,
+so they become equally sized to Apple's own icons.

Makefile

@@ -1,11 +1,22 @@
-# Output directory
 RESOURCES_DIR := Resources
 
+# Icon files and names
 ICON_FILES := $(shell find Icons/ -depth 1 -name '*.icon')
+ICON_NAMES := $(basename $(notdir $(ICON_FILES)))
 ICON_SOURCES := $(shell find $(ICON_FILES) -type f)
 
+# *.icns files
+ICNS_VARIANTS := \
+	Default \
+	Dark
+ICNS_FILES := $(foreach \
+	icon,$(ICON_NAMES), \
+	$(foreach variant,$(ICNS_VARIANTS), \
+		$(RESOURCES_DIR)/$(icon)-$(variant).icns \
+	))
+
 .PHONY: all
-all: $(RESOURCES_DIR)/Assets.car
+all: $(RESOURCES_DIR)/Assets.car $(ICNS_FILES)
 
 $(RESOURCES_DIR)/Assets.car: $(ICON_FILES) $(ICON_SOURCES)
 	mkdir -p "$(RESOURCES_DIR)"
@@ -22,6 +33,16 @@ $(RESOURCES_DIR)/Assets.car: $(ICON_FILES) $(ICON_SOURCES)
 		--platform macosx \
 		--minimum-deployment-target 11.0
 
+# *.icns files generation rule
+define ICNS_RULE
+$(RESOURCES_DIR)/%-$(1).icns: Icons/Exports/%-macOS-$(1)-1024x1024@2x.png
+	@mkdir -p $(RESOURCES_DIR)
+	bin/png2icns "$$<" "$$@"
+endef
+
+$(foreach variant,$(ICNS_VARIANTS),$(eval $(call ICNS_RULE,$(variant))))
+
 .PHONY: clean
 clean:
 	find "$(RESOURCES_DIR)" -type f -name 'Assets.car' -delete
+	find "$(RESOURCES_DIR)" -type f -name '*.icns' -delete

bin/png2icns

@@ -0,0 +1,177 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+usage() {
+  echo "Usage: $(basename "$0") <source.png> [output.icns]" >&2
+}
+
+gen-png() {
+  local src="$1"
+  local px="$2"
+  local dpi="$3"
+  local out="$4"
+
+  # Resize longest side to <px>, then pad to a square <px>x<px> with transparency.
+  local tmp_resized
+  tmp_resized="${out}.tmp.png"
+
+  # Scale preserving aspect ratio; longest side becomes <px>.
+  sips -Z "$px" "$src" --out "$tmp_resized" > /dev/null
+
+  # Pad to exact square dimensions centered on transparent background.
+  sips --padToHeightWidth "$px" "$px" \
+    "$tmp_resized" --out "$out" > /dev/null
+
+  rm -f "$tmp_resized" || true
+
+  # Set DPI metadata.
+  sips -s dpiHeight "$dpi" -s dpiWidth "$dpi" "$out" > /dev/null
+}
+
+get-image-max-dim() {
+  local src="$1"
+  local w h
+
+  # Capture width/height; avoid exiting on failure due to set -e/pipefail.
+  w=$(sips -g pixelWidth "$src" 2> /dev/null |
+    awk '/pixelWidth/ {print $2}') || true
+  h=$(sips -g pixelHeight "$src" 2> /dev/null |
+    awk '/pixelHeight/ {print $2}') || true
+
+  if [[ -z "$w" || -z "$h" ]]; then
+    echo "Failed to read image dimensions with sips: $src" >&2
+    return 1
+  fi
+
+  if ((w > h)); then
+    echo "$w"
+  else
+    echo "$h"
+  fi
+}
+
+verify-png() {
+  local src="$1"
+  local fmt
+  fmt=$(sips -g format "$src" 2> /dev/null |
+    awk '/format/ {print tolower($2)}') || true
+  if [[ -z "$fmt" ]]; then
+    echo "Unable to determine image format with sips: $src" >&2
+    return 1
+  fi
+  if [[ "$fmt" != "png" ]]; then
+    echo "Input must be a PNG image: $src" >&2
+    return 1
+  fi
+}
+
+make-iconset() {
+  local src="$1"
+  local dest_dir="$2"
+
+  mkdir -p "$dest_dir"
+
+  # Sizes to generate (@1x). @2x files are double the pixels.
+  local sizes=(16 32 128 256 512)
+
+  # Determine maximum source dimension to avoid upscaling.
+  local src_max
+  if ! src_max=$(get-image-max-dim "$src"); then
+    return 1
+  fi
+
+  local generated
+  generated=0
+
+  for sz in "${sizes[@]}"; do
+    # @1x
+    local out1="${dest_dir}/icon_${sz}x${sz}.png"
+    if ((sz <= src_max)); then
+      gen-png "$src" "$sz" 72 "$out1"
+      generated=$((generated + 1))
+    fi
+
+    # @2x (double pixels, higher DPI)
+    local dsz=$((sz * 2))
+    local out2="${dest_dir}/icon_${sz}x${sz}@2x.png"
+    if ((dsz <= src_max)); then
+      gen-png "$src" "$dsz" 144 "$out2"
+      generated=$((generated + 1))
+    fi
+  done
+
+  if ((generated == 0)); then
+    echo "Source image too small; no icon sizes generated: $src" >&2
+    return 1
+  fi
+}
+
+cleanup() {
+  local path="$1"
+
+  if [[ -z "$path" || ! -d "$path" ]]; then
+    return 0
+  fi
+
+  # Remove generated PNGs inside the temp directory
+  find "$path" -type f -name '*.png' -delete 2> /dev/null || true
+
+  # Remove generated `*.iconset` inside the temp directory
+  find "$path" -type d -name '*.iconset' -delete 2> /dev/null || true
+
+  # Attempt to remove the temp directory if now empty
+  rmdir "$path" 2> /dev/null || true
+}
+
+main() {
+  if [[ $# -lt 1 || $# -gt 2 ]]; then
+    usage
+    exit 1
+  fi
+
+  local src="$1"
+  local out="${2:-${src%.*}.icns}"
+
+  if [[ ! -f "$src" ]]; then
+    echo "Source file not found: $src" >&2
+    exit 1
+  fi
+
+  if ! command -v sips > /dev/null 2>&1; then
+    echo "This script requires 'sips' (macOS) but it wasn't found." >&2
+    exit 1
+  fi
+
+  if ! command -v iconutil > /dev/null 2>&1; then
+    echo "This script requires 'iconutil' (macOS) but it wasn't found." >&2
+    exit 1
+  fi
+
+  local outdir
+  outdir="$(dirname "$out")"
+  mkdir -p "$outdir"
+
+  # Create a temporary working directory
+  tmp_root="$(mktemp -d 2> /dev/null || mktemp -d -t png2icns)"
+  trap 'cleanup "$tmp_root"' EXIT
+
+  # Verify input is PNG; we do not accept other formats.
+  if ! verify-png "$src"; then
+    exit 1
+  fi
+
+  local iconset_dir
+  iconset_dir="${tmp_root}/icon.iconset"
+
+  make-iconset "$src" "$iconset_dir"
+
+  # Build `.icns` from the generated iconset
+  if ! iconutil -c icns -o "$out" "$iconset_dir" 2> /dev/null; then
+    echo "Failed to create .icns with iconutil" >&2
+    exit 1
+  fi
+
+  echo "Done. ICNS written to: $out"
+}
+
+main "$@"