move image size stuff to a separate function we can call on demand

libs/arg.c

@@ -305,25 +305,7 @@ setimgsize(const Arg *arg)
     return;
     #endif
 
-    /* this makes sure we cannot scale down the image too much */
-    if ((!image && imageheight + arg->i < imageheight) || hideimage) return;
-
-    cleanupimage();
-
-    imageheight += arg->i;
-    imagewidth += arg->i;
-
-    drawimage();
-
-    if (!image) {
-        imageheight -= arg->i;
-        imagewidth -= arg->i;
-        return;
-    } else {
-        drawimage();
-    }
-
-    drawmenu();
+    setimagesize(imagewidth + arg->i, imageheight + arg->i);
 }
 
 void

libs/img.c

@@ -1,3 +1,35 @@
+void
+setimagesize(int width, int height)
+{
+    #if !USEIMAGE
+    return;
+    #endif
+
+    int oih = 0;
+    int oiw = 0;
+
+    /* this makes sure we cannot scale down the image too much */
+    if ((!image && height < imageheight) || (!image && width < imagewidth) || hideimage) return;
+
+    cleanupimage();
+
+    oih = imageheight;
+    oiw = imagewidth;
+
+    imageheight = height;
+    imagewidth = width;
+
+    drawimage();
+
+    if (!image) {
+        imageheight = oih;
+        imagewidth = oiw;
+        return;
+    }
+
+    drawmenu();
+}
+
 void
 flipimage(void)
 {

libs/img.h

@@ -3,6 +3,7 @@
 #include <Imlib2.h>
 #include <openssl/md5.h>
 
+static void setimagesize(int width, int height);
 static void setimageopts(void);
 static void cleanupimage(void);
 static void drawimage(void);