lighttroupe/luz

#
# Image loading, caching, and reloading upon changes (using inotify)
#
multi_require 'image_thumbnailer'

module EngineImages
    SUPPORTED_IMAGE_EXTENSIONS = ['png','jpg','jpeg','bmp','gif']

    #
    # API
    #
    def load_image(path)
        if (images=load_images(path))
            images.first
        end
    end

    def load_image_thumbnail(path, &proc)
        thumbnailer.add(path) { |thumbnail_path|
            image = load_image(thumbnail_path)
            proc.call(image) if image
        }
    end

    def load_images(relative_path)
        @images_cache ||= {}

        relative_path = relative_path.without_prefix(@project.file_path) if @project.file_path

        file_path = find_file_by_relative_path(relative_path)

        # Note: cache using the full path name, so that two projects with similar relative paths won't get confused
        return @images_cache[file_path] if @images_cache[file_path]

        unless file_path && File.exists?(file_path)
            puts "Engine#load_images: file doesn't exist \"#{file_path}\"" 
            return (@images_cache[file_path] ||= [Image.new])
        end

        return_value = nil
        with_watch(file_path) {
            @images_cache[file_path] ||= []        # DO NOT replace with [] as that would invalidate external object references

            timer("load #{relative_path}", :if_over => 0.1) {
                case File.extname(file_path).downcase
                when '.png', '.jpg', '.jpeg', '.bmp'
                    @images_cache[file_path][0] ||= Image.new
                    @images_cache[file_path][0].from_image_file_path(file_path)
                    return_value = @images_cache[file_path]
                when '.gif'
                    begin
                        list = Magick::ImageList.new(file_path).coalesce
                        image_list = @images_cache[file_path]
                        list.each_with_index { |rmagick_image, index| image_list[index] ||= Image.new ; image_list[index].load_from_rmagick_image(rmagick_image) }
                        return_value = image_list
                    rescue
                        return_value = false
                    end
                else
                    puts "unhandled image file type for #{file_path}"
                    return_value = false
                end
            }
            true        # tell with_watch that we were successful
        }
        return_value
    end

private

    # given an absolute or relative path, find an existing file in one of the registered image directories
    def find_file_by_relative_path(relative_path)
        ([relative_path] + image_directories.map { |dir| File.join(dir, relative_path) }).find { |p|
            File.exists?(p)
        }
    end

    def image_directories
        [@project.file_path, 'gui'].compact
    end

    def thumbnailer
        @thumbnailer ||= ImageThumbnailer.new
    end
end