Fix SVG side by side comparison link (go-gitea#17375)

* Remove swipe-bar z-index

Fixes position of swipe-bar so it does not overlay other UI components when scrolling.

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Unique names for image tabs in pull request

Define unique names for image tabs in pull requests, in order to toggle tabs correctly when multiple are displayed on one page.

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

templates/repo/diff/image_diff.tmpl

@@ -6,15 +6,15 @@
 		<div class="image-diff" data-path-before="{{$imagePathOld}}" data-path-after="{{$imagePathNew}}">
 			<div class="ui secondary pointing tabular top attached borderless menu stackable new-menu">
 				<div class="new-menu-inner">
-					<a class="item active" data-tab="diff-side-by-side">{{.root.i18n.Tr "repo.diff.image.side_by_side"}}</a>
+					<a class="item active" data-tab="diff-side-by-side-{{ .file.Index }}">{{.root.i18n.Tr "repo.diff.image.side_by_side"}}</a>
 					{{if and .blobBase .blobHead}}
-					<a class="item" data-tab="diff-swipe">{{.root.i18n.Tr "repo.diff.image.swipe"}}</a>
-					<a class="item" data-tab="diff-overlay">{{.root.i18n.Tr "repo.diff.image.overlay"}}</a>
+					<a class="item" data-tab="diff-swipe-{{ .file.Index }}">{{.root.i18n.Tr "repo.diff.image.swipe"}}</a>
+					<a class="item" data-tab="diff-overlay-{{ .file.Index }}">{{.root.i18n.Tr "repo.diff.image.overlay"}}</a>
 					{{end}}
 				</div>
 			</div>
 			<div class="hide">
-				<div class="ui bottom attached tab image-diff-container active" data-tab="diff-side-by-side">
+				<div class="ui bottom attached tab image-diff-container active" data-tab="diff-side-by-side-{{ .file.Index }}">
 					<div class="diff-side-by-side">
 						{{if .blobBase }}
 						<span class="side">
@@ -49,7 +49,7 @@
 					</div>
 				</div>
 				{{if and .blobBase .blobHead}}
-				<div class="ui bottom attached tab image-diff-container" data-tab="diff-swipe">
+				<div class="ui bottom attached tab image-diff-container" data-tab="diff-swipe-{{ .file.Index }}">
 					<div class="diff-swipe">
 						<div class="swipe-frame">
 							<span class="before-container"><img class="image-before" /></span>
@@ -63,7 +63,7 @@
 						</div>
 					</div>
 				</div>
-				<div class="ui bottom attached tab image-diff-container" data-tab="diff-overlay">
+				<div class="ui bottom attached tab image-diff-container" data-tab="diff-overlay-{{ .file.Index }}">
 					<div class="diff-overlay">
 						<div class="overlay-frame">
 							<div class="ui centered">

web_src/less/features/imagediff.less

@@ -54,7 +54,6 @@
       }
 
       .swipe-bar {
-        z-index: 100;
         position: absolute;
         height: 100%;
         top: 0;