Linked libraries no longer automatically required

README.md

@@ -1,4 +1,4 @@
-# Crystal Image (Processing)
+# [Crystal Image (Processing)](http://troy.sornson.io/cr-image/)
 
 This shard aims to provide feature rich image processing abilities, both for the purpose of
 image manipulation as well as feature / information extraction from those images.
@@ -22,6 +22,23 @@ All sample images used are from [Unsplash](https://unsplash.com/).
 
 ## Usage
 
+CrImage supports the formats:
+* PPM
+* JPEG (requires `libturbojpeg`)
+* PNG (requirens `libspng`)
+* WebP (requires `libwebp`)
+
+For the formats that require a linked library, they must be `require`d explicitly:
+
+```crystal
+require "cr-image"
+require "cr-image/jpeg"
+require "cr-image/png"
+require "cr-image/webp"
+```
+
+### Example
+
 Assuming an image `moon.jpg` already exists
 
 <img src="https://raw.githubusercontent.com/Vici37/cr-image/master/docs/images/moon.jpg" alt="Picture of moon"/>

spec/spec_helper.cr

@@ -1,6 +1,9 @@
 require "digest"
 require "spectator"
 require "../src/cr-image"
+require "../src/jpeg"
+require "../src/png"
+require "../src/webp"
 require "./helpers/**"
 
 module SpecHelper

src/cr-image.cr

@@ -1 +1,15 @@
-require "./cr-image/**"
+require "./cr-image/operation/*"
+require "./cr-image/format/save"
+require "./cr-image/format/open"
+
+# Native crystal image format implementations
+require "./cr-image/format/ppm"
+
+require "./cr-image/channel_type"
+require "./cr-image/color"
+require "./cr-image/exception"
+require "./cr-image/mask"
+require "./cr-image/region"
+require "./cr-image/image"
+require "./cr-image/grayscale_image"
+require "./cr-image/rgba_image"

src/cr-image/format/open.cr

@@ -12,12 +12,13 @@
 module CrImage::Format::Open
   # Reads this image from file using the provided filename.
   def open(filename : String) : self
+    {% begin %}
     case filename
-    when .ends_with?(".ppm")                       then File.open(filename) { |f| self.from_ppm(f) }
-    when .ends_with?(".jpg"), .ends_with?(".jpeg") then File.open(filename) { |f| self.from_jpeg(f) }
-    when .ends_with?(".webp")                      then File.open(filename) { |f| self.from_webp(f) }
-    when .ends_with?(".png")                       then File.open(filename) { |f| self.from_png(f) }
-    else                                                raise "Unknown file extension for filename #{filename}, only support .webp, .png, .ppm, .jpg, and .jpeg"
+    {% for format in SUPPORTED_FORMATS %}
+      when .ends_with?({{format[:extension]}}) then File.open(filename) { |file| self.from_{{format[:method].id}}(file) }
+    {% end %}
+      else raise Exception.new "Unknown file extension for filename #{filename}, cr-image only supports {{CrImage::Format::SUPPORTED_FORMATS.map(&.[:extension].id).join(", ").id}}"
     end
+    {% end %}
   end
 end

src/cr-image/format/ppm.cr

@@ -11,6 +11,8 @@
 # image.save("other_image.ppm")
 # ```
 module CrImage::Format::PPM
+  {% CrImage::Format::SUPPORTED_FORMATS << {extension: ".ppm", method: "ppm"} %}
+
   macro included
     # Read `image_data` as PPM encoded bytes
     def self.from_ppm(image_data : Bytes) : self

src/cr-image/format/save.cr

@@ -9,21 +9,27 @@
 # image.save("image.jpg")
 # ```
 # See `Open` for a convenience method to read images from the filesystem
-module CrImage::Format::Save
-  # Write this image to file using the provided filename.
-  #
-  # This method _will not_ create intermediate directory paths. This method will throw an
-  # error if they don't exist.
-  def save(filename : String) : self
-    File.open(filename, "w") do |file|
-      case filename
-      when .ends_with?(".ppm")                       then to_ppm(file)
-      when .ends_with?(".jpg"), .ends_with?(".jpeg") then to_jpeg(file)
-      when .ends_with?(".webp")                      then to_webp(file)
-      when .ends_with?(".png")                       then to_png(file)
-      else                                                raise "Unknown file extension for filename #{filename}, only support .webp, .png, .ppm, .jpg, and .jpeg"
+module CrImage::Format
+  SUPPORTED_FORMATS = [] of Nil
+
+  module Save
+    # Write this image to file using the provided filename.
+    #
+    # This method _will not_ create intermediate directory paths. This method will throw an
+    # error if they don't exist.
+    def save(filename : String) : self
+      File.open(filename, "w") do |file|
+        {% begin %}
+        case filename
+        {% for format in SUPPORTED_FORMATS %}
+          when .ends_with?({{format[:extension]}}) then to_{{format[:method].id}}(file)
+        {% end %}
+          else raise Exception.new "Unknown file extension for filename #{filename}, cr-image only supports {{CrImage::Format::SUPPORTED_FORMATS.map(&.[:extension].id).join(", ").id}}"
+        end
+        {% end %}
       end
     end
+
     self
   end
 end

src/cr-image/image.cr

@@ -1,15 +1,16 @@
-require "./bindings/*"
-require "./format/*"
-require "./operation/*"
-
 # Common base class for `GrayscaleImage` and `RGBAImage`. All `Image`s are readable and saveable
 # to the filesystem or `IO` stream.
 abstract class CrImage::Image
+  macro subsclasses_include(mod)
+    {% for sub in @type.subclasses %}
+      class ::{{sub}}
+        include {{mod}}
+      end
+    {% end %}
+  end
+
   macro inherited
-    include Format::JPEG
     include Format::PPM
-    include Format::WebP
-    include Format::PNG
 
     include Operation::BilinearResize
     include Operation::BoxBlur

src/cr-image/rgba_image.cr

@@ -1,8 +1,3 @@
-require "./image"
-require "./bindings/*"
-require "./format/*"
-require "./operation/*"
-
 # An image with red, green, blue, and alpha color channels (i.e. a color image). This image type is likely the one read from and written to file (or `IO`).
 class CrImage::RGBAImage < CrImage::Image
   property red : Array(UInt8)

src/jpeg.cr

@@ -0,0 +1,4 @@
+require "./cr-image"
+require "./lib-formats/jpeg"
+
+CrImage::Image.subsclasses_include(CrImage::Format::JPEG)

src/cr-image/format/jpeg.cr → src/lib-formats/jpeg.cr

@@ -1,4 +1,4 @@
-require "../bindings/lib_jpeg_turbo"
+require "./bindings/lib_jpeg_turbo"
 
 # Provides methods to read from and write to jpeg. Requires `libturbojpeg` to function.
 #
@@ -13,6 +13,11 @@ require "../bindings/lib_jpeg_turbo"
 # image.save("other_image.jpg")
 # ```
 module CrImage::Format::JPEG
+  {%
+    CrImage::Format::SUPPORTED_FORMATS << {extension: ".jpeg", method: "jpeg"}
+    CrImage::Format::SUPPORTED_FORMATS << {extension: ".jpg", method: "jpeg"}
+  %}
+
   macro included
     # Read `image_data` as JPEG encoded bytes
     def self.from_jpeg(image_data : Bytes) : self

src/cr-image/format/png.cr → src/lib-formats/png.cr

@@ -1,4 +1,4 @@
-require "../bindings/lib_spng"
+require "./bindings/lib_spng"
 
 # Provides methods to read from and write to PNG. Requires `libspng` to function.
 #
@@ -13,6 +13,8 @@ require "../bindings/lib_spng"
 # image.save("other_image.png")
 # ```
 module CrImage::Format::PNG
+  {% CrImage::Format::SUPPORTED_FORMATS << {extension: ".png", method: "png"} %}
+
   macro included
     # Read `image_data` and PNG encoded bytes
     def self.from_png(image_data : Bytes) : self

src/cr-image/format/webp.cr → src/lib-formats/webp.cr

@@ -1,4 +1,4 @@
-require "../bindings/lib_webp"
+require "./bindings/lib_webp"
 
 # Provides methods to read from and write to WebP. Requires `libwebp` to function.
 #
@@ -13,6 +13,8 @@ require "../bindings/lib_webp"
 # image.save("other_image.webp")
 # ```
 module CrImage::Format::WebP
+  {% CrImage::Format::SUPPORTED_FORMATS << {extension: ".webp", method: "webp"} %}
+
   macro included
     # Read `image_data` as WebP encoded bytes
     def self.from_webp(image_data : Bytes) : self

src/png.cr

@@ -0,0 +1,4 @@
+require "./cr-image"
+require "./lib-formats/png"
+
+CrImage::Image.subsclasses_include(CrImage::Format::PNG)

src/webp.cr

@@ -0,0 +1,4 @@
+require "./cr-image"
+require "./lib-formats/webp"
+
+CrImage::Image.subsclasses_include(CrImage::Format::WebP)