Crushed PNGs, EXIF embedding for AVIF

- Support for Crushed PNGs has been added.
- EXIF metadata is now embedded in AVIF files as well as PNG.
- Documentation has been updated to reflect the new crushed PNG format.
- New metadata documentation for showing how to add licensing metadata to images.

README.md

@@ -32,10 +32,10 @@ Mutant Standard's [code of conduct](docs/code_of_conduct.md).
 
 - Declarative language for defining semantics of emoji set
 - Color mapping (recoloring)
-- Outputting emoji both as shortcode-named files (ie. 'ice_cream') and unicode codepoint-named files (ie. '1f368').
-- SVG, PNG, Lossless WebP, Lossless AVIF and FLIF exports
-- Optional space-saving optimisations for SVG files
-- Supports multiple SVG renderers: rendersvg, Inkscape and ImageMagick
+- Outputting emoji both as shortcode-named files (ie. 'ice_cream') and unicode codepoint-named files (ie. '1f368')
+- Export to SVG, PNG, Lossless WebP, Lossless AVIF and FLIF
+- Optional lossless crushing of SVG and PNG files
+- Supports multiple SVG renderers (rendersvg, Inkscape and ImageMagick)
 - Output options including emoji filtering, customisable export directory
   structure and filenaming
 - JSON output of emoji set metadata
@@ -53,6 +53,7 @@ Mutant Standard's [code of conduct](docs/code_of_conduct.md).
     - ImageMagick
 - exiftool (Optional; for embedding EXIF license metadata)
 - [svgcleaner](https://github.com/RazrFalcon/svgcleaner) (Optional; for Optimised SVG output)
+- [oxipng](https://github.com/shssoichiro/oxipng) (Optional; for Crushed PNG output)
 - [FLIF](https://github.com/FLIF-hub/FLIF) (Optional; for FLIF output)
 - [libwebp](https://developers.google.com/speed/webp/docs/precompiled) (Optional; for Lossless WebP output)
 - [go-avif](https://github.com/Kagami/go-avif) (Optional; for AVIF output) (Experimental; does not currently produce truly lossless images. We're trying to figure out why that is.)

dest_paths.py

@@ -66,6 +66,8 @@ def format_path(path, emoji, format):
         res = res + '.svg'
     elif format.startswith('png-'):
         res = res + '.png'
+    elif format.startswith('pngc-'):
+        res = res + '.png'
     elif format.startswith('flif-'):
         res = res + '.flif'
     elif format.startswith('webp-'):

docs/dzuk/howto.md

@@ -60,6 +60,12 @@ Using this means that you're just exporting JSON for this command, you can't use
 
 ----
 
+# [Metadata](metadata.md)
+
+forc can embed SVG or EXIF metadata into your exported emoji sets.
+
+---
+
 # Extra flags
 
 ## Force Text Descriptions (`--force-desc`)

docs/dzuk/image_formats.md

@@ -7,15 +7,18 @@
 *(check the [readme](../../readme.md) for all the information on dependencies)*
 
 #### `svgo` Optimised SVG
-Optimised SVG is the same format as SVG, but it's losslessly compressed to create a smaller file size (in Mutant Standard tests, optimised SVGs are 30-40% smaller). It requires an extra processing stage, and it needs the dependency listed. Check the [svgcleaner](https://github.com/RazrFalcon/svgcleaner) repo to see the documentation for it so you can see what it does to the SVG files.
+Optimised SVG is the same format as SVG, but it's losslessly compressed to create a smaller file size. It requires an extra processing stage (which is very cheap on CPU), and it needs the dependency listed. Check the [svgcleaner](https://github.com/RazrFalcon/svgcleaner) repo to see the documentation for it so you can see what it does to the SVG files.
 
-orxporter uses svgcleaner with the following settings:
+orxporter uses svgcleaner with the following command:
 
 `svgcleaner <in file> <out file> --remove-metadata=no --quiet`
 
+In Mutant Standard tests, optimised SVGs are 30-40% smaller than normal SVGs. Unless you're doing something in particular, it's probably worth using Optimise SVGs by default instead of SVGs in your workflow.
+
 
 ### Raster
 - `png` PNG
+- `pngc` Crushed PNG (requires oxipng)
 - `webp` Lossless WebP (requires cwebp)
 - `avif` Lossless AVIF (requires go-avif)
 - `flif` FLIF (requires flif)
@@ -32,3 +35,13 @@ avif-128
 webp-512
 png-60
 ```
+
+#### `pngc` Crushed PNG
+Crushed PNG is the same format as PNG, but it's losslessly compressed to create a smaller file size. It requires an extra processing stage (which can be quite expensive on CPU at very large sizes like 512px), and it needs the dependency listed. Check the [oxipng](https://github.com/shssoichiro/oxipng) repo to see the documentation for it so you can see what it does to the PNG files.
+
+orxporter uses oxipng with the following command:
+
+`oxipng <in file> --out, <out file> --quiet`
+
+In Mutant Standard tests, Crushed PNGs have a file size reduction of about 25% compared to normal PNGs, but only on larger sizes (128px upwards).
+At 32px, crushing PNGs only has an average file size reduction of 3%.

docs/dzuk/metadata.md

@@ -0,0 +1,66 @@
+# Metadata (Licenses)
+
+Orxporter can embed metadata into your resulting emoji. This is useful if you want to put author or license information into your work for public distribution.
+
+You add metadata to your manifests using the orx keyword `license`, as shown below:
+
+```
+license svg = license/svg.xml		exif = license/exif.json
+```
+
+Metadata is automatically embedded in your resulting images, but if you want to leave it out...
+
+- Use the flag `-l` if you're using the [simple exporting method](image_easy,md).
+- Use `license = no` in your Parameters file if you're using the [advanced exporting method](image_advanced),
+
+Metadata embedding is only done with certain formats:
+
+- EXIF metadata can be embedded in PNG and AVIF files.
+- SVG metadata can be embedded in SVG files.
+
+---
+
+## `svg`: SVG Metadata
+
+SVG Metadata is an XML file you create that contains stuff that gets inserted in the `<metadata>` tag of your resulting SVGs.
+
+Below is an example XML file with Mutant Standard's SVG metadata:
+
+```
+<rdf:RDF xmlns:cc="http://web.resource.org/cc/"
+         xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+         xmlns:dc = "http://purl.org/dc/elements/1.1/"
+         >
+
+     <rdf:Description rdf:about="">
+       <dc:title>Mutant Standard emoji v0.4.1</dc:title>
+     </rdf:Description>
+
+    <cc:work rdf:about="">
+        <cc:license rdf:resource="http://creativecommons.org/licenses/by-nc-sa/4.0/"/>
+        <cc:attributionName>Dzuk</cc:attributionName>
+        <cc:attributionURL>http://mutant.tech/</cc:attributionURL>
+    </cc:work>
+
+</rdf:RDF>
+```
+
+---
+
+## `exif`: EXIF Metadata
+
+EXIF Metadata is a JSON file you create that contains stuff that gets inserted in the EXIF metadata of your resulting raster images.
+
+Below is an example JSON file with Mutant Standard's EXIF metadata:
+
+```
+{
+    "XMP-dc:title": "Mutant Standard emoji v0.4.1",
+    "XMP-dc:rights": "This work is licensed to the public under the Attribution-NonCommercial-ShareAlike 4.0 International license https://creativecommons.org/licenses/by-nc-sa/4.0/",
+    "XMP-xmpRights:UsageTerms": "This work is licensed to the public under the Attribution-NonCommercial-ShareAlike 4.0 International license https://creativecommons.org/licenses/by-nc-sa/4.0/",
+    "XMP-cc:AttributionName": "Dzuk",
+    "XMP-cc:AttributionURL": "mutant.tech",
+    "XMP-cc:License": "https://creativecommons.org/licenses/by-nc-sa/4.0/"
+}
+
+```

docs/kiilas/manifest.md

@@ -258,7 +258,7 @@ The *svg* parameter must point to a file containing the desired string to be
 inserted inside each SVG file's *metadata* tag.
 
 The *exif* parameter must point to a JSON file containing a single object with
-the desired EXIF tags to be written to each PNG file.
+the desired EXIF tags to be written to each PNG or AVIF file.
 
 Text descriptions
 -----------------

export.py

@@ -129,7 +129,8 @@ def export(m, filtered_emoji, input_path, formats, path, src_size,
         png_files = []
         for e in exporting_emoji:
             for f in formats:
-                if f.startswith('png-'):
+                # png, pngc or avif
+                if f.startswith('png') or f.startswith('avif-'):
                     try:
                         png_files.append(format_path(path, e, f))
                     except FilterException:

export_task.py

@@ -51,7 +51,9 @@ def to_raster(emoji_svg, out_path, renderer, format, size, name):
         # two-step process
         image_proc.render_svg(tmp_svg_path, tmp_png_path, renderer, size)
 
-        if format == "webp":
+        if format == "pngc":
+            image_proc.crush_png(tmp_png_path, out_path)
+        elif format == "webp":
             image_proc.convert_webp(tmp_png_path, out_path)
         elif format == "avif":
             image_proc.convert_avif(tmp_png_path, out_path)

export_thread.py

@@ -88,6 +88,9 @@ def export_emoji(self, emoji, emoji_svg, f, path, license):
             if raster_format[0] == "png":
                 export_task.to_raster(emoji_svg, final_path, self.renderer, "png", size, self.name)
 
+            elif raster_format[0] == "pngc":
+                export_task.to_raster(emoji_svg, final_path, self.renderer, "pngc", size, self.name)
+
             elif raster_format[0] == "webp":
                 export_task.to_raster(emoji_svg, final_path, self.renderer, "webp", size, self.name)
 

orxport.py

@@ -53,12 +53,13 @@
 ----------------------------------------------------
 -F      Format (default: {DEF_OUTPUT_FORMATS[0]})
         comma separated with no spaces (ie. 'svg,png-64,flif-128')
-        - svg
-        - svgo
-        - png-SIZE
-        - flif-SIZE
-        - webp-SIZE
-        - avif-SIZE
+        - svg (SVG)
+        - svgo (Optimised SVG)
+        - png-SIZE (PNG)
+        - pngc-SIZE (Crushed PNG)
+        - flif-SIZE (FLIF)
+        - webp-SIZE (Lossless WebP)
+        - avif-SIZE (Lossless AVIF)
 
 -f      Directory/filename naming system for output (default: {DEF_OUTPUT_NAMING})
         See the documentation for how this works.