allow either target width or height to be zero

diff --git a/lib/devices/rescale.c b/lib/devices/rescale.c
index e82aed6..b8530b9 100644 (file)
--- a/lib/devices/rescale.c
+++ b/lib/devices/rescale.c
@@ -137,31 +137,37 @@ void rescale_startpage(gfxdevice_t*dev, int width, int height)
     i->origwidth = width;
     i->origheight = height;
 
-    if(i->targetwidth && i->targetheight) {
+    if(i->targetwidth || i->targetheight) {
+        int targetwidth = i->targetwidth;
+        if(!targetwidth)
+            targetwidth = width*i->targetheight/height;
+        int targetheight = i->targetheight;
+        if(!targetheight)
+            targetheight = height*i->targetwidth/width;
        if(i->keepratio) {
-           double rx = (double)i->targetwidth / (double)width;
-           double ry = (double)i->targetheight / (double)height;
+           double rx = (double)targetwidth / (double)width;
+           double ry = (double)targetheight / (double)height;
            if(rx<ry) {
                i->matrix.m00 = rx;
                i->matrix.m11 = rx;
                i->matrix.tx = 0;
                if(i->centery) {
-                   i->matrix.ty = (i->targetheight - height*rx) / 2;
+                   i->matrix.ty = (targetheight - height*rx) / 2;
                }
            } else {
                i->matrix.m00 = ry;
                i->matrix.m11 = ry;
                if(i->centerx) {
-                   i->matrix.tx = (i->targetwidth - width*ry) / 2;
+                   i->matrix.tx = (targetwidth - width*ry) / 2;
                }
                i->matrix.ty = 0;
            }
        } else {
-           i->matrix.m00 = (double)i->targetwidth / (double)width;
-           i->matrix.m11 = (double)i->targetheight / (double)height;
+           i->matrix.m00 = (double)targetwidth / (double)width;
+           i->matrix.m11 = (double)targetheight / (double)height;
        }
        i->zoomwidth = sqrt(i->matrix.m00*i->matrix.m11);
-       i->out->startpage(i->out,i->targetwidth,i->targetheight);
+       i->out->startpage(i->out,targetwidth,targetheight);
     } else {
        i->out->startpage(i->out,(int)(width*i->matrix.m00),(int)(height*i->matrix.m11));
     }