Add css-images-4.vim

See also: http://www.w3.org/TR/2017/WD-css-images-4-20170413/

This commit also moves some properties and functions from
`css3-images.vim`.

Author: hail2u

after/syntax/css/css-images-4.vim

@@ -0,0 +1,2 @@
+syn match cssFontProp contained "\<image-resolution\>"
+syn region cssFunction contained matchgroup=cssFunctionName start="\<\(image\|element\|conic-gradient\)\s*(" end=")" oneline keepend

after/syntax/css/css3-images.vim

@@ -1,7 +1,6 @@
-" TODO: create cssImagesProp group and cssImagesAttr group
 syn match cssFontProp contained "\<object-\(fit\|position\)\>"
-syn match cssFontProp contained "\<image-\(resolution\|orientation\)\>"
+syn match cssFontProp contained "\<image-orientation\>"
 syn keyword cssFontAttr contained contain cover snap
 syn match cssFontAttr contained "\<from-image\>"
 syn match cssFontAttr contained "\<scale-down\>"
-syn region cssFunction contained matchgroup=cssFunctionName start="\<\(image\|\(repeating-\)\=\(linear\|radial\)-gradient\)\s*(" end=")" oneline keepend
+syn region cssFunction contained matchgroup=cssFunctionName start="\<\(\(repeating-\)\=\(linear\|radial\)-gradient\)\s*(" end=")" oneline keepend

after/syntax/html.vim

@@ -16,6 +16,7 @@ syn include @htmlCss syntax/css/css-fonts-3.vim
 syn include @htmlCss syntax/css/css-fonts-4.vim
 syn include @htmlCss syntax/css/css-gcpm-3.vim
 syn include @htmlCss syntax/css/css-grid-1.vim
+syn include @htmlCss syntax/css/css-images-4.vim
 syn include @htmlCss syntax/css/css-inline-3.vim
 syn include @htmlCss syntax/css/css-line-grid-1.vim
 syn include @htmlCss syntax/css/css-lists-3.vim

test/test.css

@@ -363,19 +363,24 @@
   grid-gap: auto;
 }
 
-.images {
+.images-3 {
   object-fit: contain;
   object-position: cover;
-  image-resolution: snap;
-  image-orientation: scale-down;
+  image-orientation: snap;
+  display: scale-down;
   display: from-image;
-  display: image("sprite.svg#xywh=40,0,20,20");
   display: linear-gradient(to bottom, yellow, blue);
   display: radial-gradient(farthest-corner at 50% 50%, yellow, green);
   display: repeating-linear-gradient(to bottom, yellow, blue);
   display: repeating-radial-gradient(farthest-corner at 50% 50%, yellow, green);
 }
 
+.images-4 {
+  image-resolution: image("sprite.svg#xywh=40,0,20,20");
+  display: element(#test);
+  display: conic-gradient(at 25% 30%, white, black 60%);
+}
+
 .inline-3 {
   dominant-baseline: mathematical;
   alignment-baseline: ideographic;

test/test.html

@@ -404,17 +404,23 @@
 .images {
   object-fit: contain;
   object-position: cover;
-  image-resolution: snap;
-  image-orientation: scale-down;
+  image-orientation: snap;
+  display: scale-down;
   display: from-image;
-  display: image("sprite.svg#xywh=40,0,20,20");
   display: linear-gradient(to bottom, yellow, blue);
   display: radial-gradient(farthest-corner at 50% 50%, yellow, green);
   display: repeating-linear-gradient(to bottom, yellow, blue);
   display: repeating-radial-gradient(farthest-corner at 50% 50%, yellow, green);
 }
 </style>
 <style>
+.images-4 {
+  image-resolution: image("sprite.svg#xywh=40,0,20,20");
+  display: element(#test);
+  display: conic-gradient(at 25% 30%, white, black 60%);
+}
+</style>
+<style>
 .inline-3 {
   dominant-baseline: mathematical;
   alignment-baseline: ideographic;