fix webp upscale in thumbnail

jcupitt · jcupitt · commit f2576003b79c · 2017-08-18T22:08:43.000+01:00
we could try to use webp shrink on load to upscale, oops see https://github.com/jcupitt/libvips/issues/710
diff --git a/ChangeLog b/ChangeLog
@@ -2,6 +2,7 @@
 - fix transparency detection in merge, thanks Haida
 - define env var VIPS_WARNING to hide warning messages
 - shut down dzsave output earlier to help mark-sweep bindings
+- fix webp thumbnail upscale, thanks Kleis
 
 9/6/17 started 8.5.7
 - better smartcrop
diff --git a/libvips/resample/thumbnail.c b/libvips/resample/thumbnail.c
@@ -254,8 +254,11 @@ vips_thumbnail_open( VipsThumbnail *thumbnail )
 		g_info( "loading PDF/SVG with factor %g pre-scale", scale ); 
 	}
 	else if( vips_isprefix( "VipsForeignLoadWebp", thumbnail->loader ) ) {
-		shrink = vips_thumbnail_calculate_shrink( thumbnail, 
-			thumbnail->input_width, thumbnail->input_height ); 
+		shrink = VIPS_MAX( 1.0, 
+			vips_thumbnail_calculate_shrink( thumbnail, 
+				thumbnail->input_width, 
+				thumbnail->input_height ) ); 
+
 		g_info( "loading webp with factor %d pre-shrink", shrink ); 
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -254,8 +254,11 @@ vips_thumbnail_open( VipsThumbnail *thumbnail )`
`254`	`254`	`g_info( "loading PDF/SVG with factor %g pre-scale", scale );`
`255`	`255`	`}`
`256`	`256`	`else if( vips_isprefix( "VipsForeignLoadWebp", thumbnail->loader ) ) {`
`257`		`- shrink = vips_thumbnail_calculate_shrink( thumbnail,`
`258`		`- thumbnail->input_width, thumbnail->input_height );`
	`257`	`+ shrink = VIPS_MAX( 1.0,`
	`258`	`+ vips_thumbnail_calculate_shrink( thumbnail,`
	`259`	`+ thumbnail->input_width,`
	`260`	`+ thumbnail->input_height ) );`
	`261`	`+`
`259`	`262`	`g_info( "loading webp with factor %d pre-shrink", shrink );`
`260`	`263`	`}`
`261`	`264`