Add new srcset syntax per #629

docs/src/querystring/introduction.md

@@ -29,7 +29,49 @@ maintaining aspect ratio.
 then minimally cropped to meet the aspect ratio. `scale=both` ensures the image is upscaled if smaller so the result 
 is always 300x300. 
 
+## srcset syntax
 
+Our new, more compact comma-delimited syntax. It lets you use the familiar srcset width and density descriptors such as  `80w`, `70h`, `2.5x`.
 
+### Notes: 
 
+* srcset commands are comma delimited, and use `-` to separate command parameters. Ex `srcset=jpeg-100,sharp-20`
+* You can also combine them, so you don't have to do math. Ex. `&srcset=100w,2x` translates to `&w=100&zoom=2` which translates to 200px wide.
+* Since CSS pixels map to multiple device pixels, this reduces an error-prone task.
+* The default mode is `max`, so you don't need to specify it when using both width and height.
+* Quality values do not translate across encoders, a fact that is lost on many people. In this syntax, we combine the format and quality value.
+* `srcset` commands expand, internally, to `&w=100&h=100&mode=max&format=[value]&zoom=[density]&quality=[x]&webp.quality=[y]&png.quality=[z]&scale=[both|down]&f.sharpen=[pct]` etc
 
+
+### List of srcset values and what they affect
+
+* `jpeg-100` - JPEG, 100% quality
+* `jpeg` - JPEG, default quality configured in the server
+* `png-100` - PNG, 100% quality
+* `webp-100` - WebP, 100% quality
+* `webp` - WebP, default quality configured in the server
+* `webp-lossless` or `webp-l` - WebP, lossless
+* `png-lossless` or `png-l` or `png`  - PNG, lossless
+* `gif` - GIF
+* `2.5x` - 2.5x density/multiplier applied to width and height
+* `100w` - 100px wide (times the density multiplier, if specified)
+* `100h` - 100px tall
+* `fit-max` - (default) don't change the image's intrinsic aspect ratio, just constrain it within the width/height box if both are specified/
+* `fit-crop` - crop to meet aspect ratio
+* `fit-pad` - pad to meet aspect ratio
+* `fit-distort` - distort to meet aspect ratio
+* `upscale` - by default, images are only downscaled. This can cause unexpected results when using `crop` or `pad`. This option allows upscaling when needed.
+* `crop-10-20-80-90` - crop to rectangle 10%,20%,80%,90% of the source image
+* `crop-10-20-80-90,100w,100h,webp-90` - crop to rectangle 10%,20%,80%,90% of the source image, scale to 100px wide, 100px tall, WebP, 90% quality
+* `sharpen-20` - sharpen by 20%
+* `sharp-20` - sharpen by 20%
+
+#### Examples
+
+* `&srcset=webp-70,sharp-15,100w` - WebP, 70% quality, 15% sharpening, 100px wide
+* `&srcset=jpeg-80,2x,100w,sharpen-20` - JPEG, 80% quality, 2x density, 200px wide, 20% sharpening
+* `&srcset=png-90,2.5x,100w,100h,crop` - PNG, 90% quality, 250px wide, 250px tall, cropped to aspect ratio
+* `&srcset=png-lossless` - PNG, lossless
+* `&srcset=gif,crop-20-30-90-100,2.5x,100w,100h` - GIF, cropped to rectangle 20%,30%,90%,100%, 250px wide, 250px tall
+* `&srcset=webp-l,2.5x,100w,100h,crop` - WebP, lossless, cropped to aspect ratio, resized to 250px wide, 250px tall
+* `&srcset=webp-lossless,2.5x,100w,100h,upscale` - WebP, lossless, 250x250px, upscale to width & height if original image is smaller.

imageflow_riapi/src/ir4/mod.rs

@@ -3,6 +3,7 @@ use imageflow_types as s;
 
 pub mod parsing;
 mod layout;
+mod srcset;
 
 use crate::sizing;
 use crate::sizing::prelude::*;

imageflow_riapi/src/ir4/parsing.rs

@@ -7,6 +7,8 @@ use imageflow_helpers::colors::*;
 use imageflow_types::Filter;
 use imageflow_helpers::preludes::from_std::fmt::Formatter;
 
+use super::srcset::apply_srcset_string;
+
 macro_attr! {
 
 
@@ -214,7 +216,7 @@ pub enum ScalingColorspace {
 
 }
 
-pub static IR4_KEYS: [&'static str;80] = ["mode", "anchor", "flip", "sflip", "scale", "cache", "process",
+pub static IR4_KEYS: [&'static str;81] = ["mode", "anchor", "flip", "sflip", "scale", "cache", "process",
     "quality", "jpeg.quality", "zoom", "crop", "cropxunits", "cropyunits",
     "w", "h", "width", "height", "maxwidth", "maxheight", "format", "thumbnail",
      "autorotate", "srotate", "rotate", "ignoreicc", "ignore_icc_errors", //really? : "precise_scaling_ratio",
@@ -227,7 +229,7 @@ pub static IR4_KEYS: [&'static str;80] = ["mode", "anchor", "flip", "sflip", "sc
     "jpeg.turbo", "encoder", "decoder", "builder", "s.roundcorners", "paddingwidth",
     "paddingheight", "margin", "borderwidth", "decoder.min_precise_scaling_ratio",
     "png.quality","png.min_quality", "png.quantization_speed", "png.libpng", "png.max_deflate",
-    "png.lossless", "up.filter", "down.filter", "dpr", "up.colorspace"];
+    "png.lossless", "up.filter", "down.filter", "dpr", "up.colorspace", "srcset"];
 
 
 #[derive(PartialEq,Debug, Clone)]
@@ -469,6 +471,10 @@ impl Instructions{
         i.jpeg_turbo = p.parse_bool("jpeg.turbo");
 
         i.watermark_red_dot = p.parse_bool("watermark_red_dot");
+
+
+        p.apply_srcset(&mut i);
+
         i
     }
 
@@ -507,6 +513,22 @@ struct Parser<'a>{
 }
 impl<'a> Parser<'a>{
 
+    fn remove(&mut self, key: &str) -> Option<String>{
+        self.m.remove(key).map(|v| v.trim().to_owned())
+    }
+
+    fn apply_srcset(&mut self, i: &mut Instructions){
+        if let Some(srcset) = self.remove("srcset"){
+            if self.w.is_some(){
+                apply_srcset_string(i, &srcset, self.w.as_mut().unwrap());
+            }else{
+                let mut w = Vec::new();
+                apply_srcset_string(i, &srcset, &mut w);
+            }
+        }
+
+    }
+
     fn warn(&mut self, warning: ParseWarning){
         if self.w.is_some() {
             self.w.as_mut().unwrap().push(warning);
@@ -1118,13 +1140,44 @@ fn test_url_parsing() {
     t("anchor=bottomleft",  Instructions{anchor: Some((Anchor1D::Near, Anchor1D::Far)), ..Default::default()}, vec![]);
     t("watermark_red_dot=true",  Instructions{watermark_red_dot: Some(true), ..Default::default()}, vec![]);
 
+    let srcset_default = Instructions{mode: Some(FitMode::Max), ..Default::default()};
+    t("srcset=100w",  Instructions{w: Some(100), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=100h",  Instructions{h: Some(100), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=2x",  Instructions{zoom: Some(2.0), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=webp-90",  Instructions{format: Some(OutputFormat::Webp), webp_quality: Some(90.0), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=png-90",  Instructions{format: Some(OutputFormat::Png), png_quality: Some(90), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=jpeg-90",  Instructions{format: Some(OutputFormat::Jpeg), quality: Some(90), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=crop-10-20-80-90",  Instructions{cropxunits: Some(100.0), cropyunits: Some(100.0),crop: Some([10.0,20.0,80.0,90.0]), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=upscale",  Instructions{scale: Some(ScaleMode::Both), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=fit-crop",  Instructions{mode: Some(FitMode::Crop), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=fit-pad",  Instructions{mode: Some(FitMode::Pad), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=fit-distort",  Instructions{mode: Some(FitMode::Stretch), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=",  Instructions{..Default::default()}, vec![]);
+    t("srcset=sharp-20",  Instructions{f_sharpen: Some(20.0), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=sharpen-20",  Instructions{f_sharpen: Some(20.0), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=sharp-20",  Instructions{f_sharpen: Some(20.0), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=gif",  Instructions{format: Some(OutputFormat::Gif), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=png",  Instructions{format: Some(OutputFormat::Png), png_lossless: Some(true), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=png-l",  Instructions{format: Some(OutputFormat::Png), png_lossless: Some(true), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=png-lossless",  Instructions{format: Some(OutputFormat::Png), png_lossless: Some(true), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=webp-l",  Instructions{format: Some(OutputFormat::Webp), webp_lossless: Some(true), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=webp-lossless",  Instructions{format: Some(OutputFormat::Webp), webp_lossless: Some(true), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=webp",  Instructions{format: Some(OutputFormat::Webp), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=webp&webp.quality=5",  Instructions{format: Some(OutputFormat::Webp), webp_quality: Some(5.0), ..srcset_default.to_owned()}, vec![]);
+    t("srcset=webp-76,100w, 100h,2x ,sharp-20 ,fit-crop", Instructions{format: Some(OutputFormat::Webp), webp_quality: Some(76.0), w: Some(100), h: Some(100), zoom: Some(2.0), f_sharpen: Some(20.0), mode: Some(FitMode::Crop), ..srcset_default.to_owned()}, vec![]);
+
 
     expect_warning("a.balancewhite","gimp",  Instructions{a_balance_white: Some(HistogramThresholdAlgorithm::Gimp), ..Default::default()});
     expect_warning("a.balancewhite","simple",  Instructions{a_balance_white: Some(HistogramThresholdAlgorithm::Simple), ..Default::default()});
     expect_warning("crop","(0,3,80, 90)",  Instructions { crop: Some([0f64,3f64,80f64,90f64]), ..Default::default() });
     expect_warning("crop","(0,3,happy, 90)",  Instructions { crop: Some([0f64,3f64,0f64,90f64]), ..Default::default() });
     expect_warning("crop","(  a0, 3, happy, 90)",  Instructions { crop: Some([0f64,3f64,0f64,90f64]), ..Default::default() });
 
+    // expect_warning("srcset","crop,pad",  Instructions{mode: Some(FitMode::Pad), ..srcset_default.to_owned()});
+    // expect_warning("srcset","pad,crop",  Instructions{mode: Some(FitMode::Crop), ..srcset_default.to_owned()});
+    // expect_warning("srcset","png,gif",  Instructions{format: Some(OutputFormat::Gif), ..srcset_default.to_owned()});
+
+
 }
 
 #[test]