Add support for images

lib/ezdoc/image_dimensions.rb

@@ -0,0 +1,55 @@
+# frozen_string_literal: true
+
+require "fastimage"
+
+module Ezdoc
+  class ImageDimensions
+    EMUS_PER_INCH = 914_400
+    DEFAULT_DPI = 96
+
+    def self.read(path)
+      FastImage.size(path) || raise(ArgumentError, "Could not read image dimensions: #{path}")
+    end
+
+    def self.calculate_emus(path, width: nil, height: nil)
+      native_width, native_height = read(path)
+      calculate_dimensions_emu(native_width, native_height, width, height)
+    end
+
+    def self.calculate_dimensions_emu(native_width, native_height, width, height)
+      if width && height
+        [parse_dimension(width), parse_dimension(height)]
+      elsif width
+        w = parse_dimension(width)
+        ratio = native_height.to_f / native_width
+        [w, (w * ratio).to_i]
+      elsif height
+        h = parse_dimension(height)
+        ratio = native_width.to_f / native_height
+        [(h * ratio).to_i, h]
+      else
+        pixels_to_emus(native_width, native_height)
+      end
+    end
+
+    def self.parse_dimension(value)
+      case value
+      when Integer
+        pixels_to_emus(value, 0).first
+      when /\A(\d+(?:\.\d+)?)\s*in\z/i
+        (::Regexp.last_match(1).to_f * EMUS_PER_INCH).to_i
+      when /\A(\d+(?:\.\d+)?)\s*cm\z/i
+        (::Regexp.last_match(1).to_f * 360_000).to_i
+      when /\A(\d+(?:\.\d+)?)\s*px\z/i, /\A(\d+)\z/
+        pixels_to_emus(::Regexp.last_match(1).to_i, 0).first
+      else
+        raise ArgumentError, "Invalid dimension format: #{value}. Use '2in', '5cm', '100px', or integer pixels."
+      end
+    end
+
+    def self.pixels_to_emus(width_px, height_px)
+      emu_per_pixel = EMUS_PER_INCH / DEFAULT_DPI
+      [(width_px * emu_per_pixel).to_i, (height_px * emu_per_pixel).to_i]
+    end
+  end
+end