From bc388368a777f14ed0a21f50dd2cb36606a6dbd9 Mon Sep 17 00:00:00 2001
From: Robby Findler <robby@racket-lang.org>
Date: Sun, 3 Sep 2006 04:03:06 +0000
Subject: [PATCH] fixed bug in image library

svn: r4230
---
 collects/htdp/image.ss             |  8 ++++----
 collects/mrlib/cache-image-snip.ss | 15 ++++++++++++---
 2 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/collects/htdp/image.ss b/collects/htdp/image.ss
index d105d5bdee..89eb3c50f6 100644
--- a/collects/htdp/image.ss
+++ b/collects/htdp/image.ss
@@ -222,10 +222,10 @@ plt/collects/tests/mzscheme/image-test.ss
                [bottom (max (+ delta-y b-h) a-h)]
                [new-w (inexact->exact (ceiling (- right left)))]
                [new-h (inexact->exact (ceiling (- bottom top)))]
-               [a-dx (- left)]
-               [a-dy (- top)]
-               [b-dx (- delta-x left)]
-               [b-dy (- delta-y top)]
+               [a-dx (inexact->exact (round (- left)))]
+               [a-dy (inexact->exact (round (- top)))]
+               [b-dx (inexact->exact (round (- delta-x left)))]
+               [b-dy (inexact->exact (round (- delta-y top)))]
                [new-px (- a-px left)]
                [new-py (- a-py top)]
                [combine (lambda (a-f b-f)
diff --git a/collects/mrlib/cache-image-snip.ss b/collects/mrlib/cache-image-snip.ss
index 8197795080..ffcbf496d6 100644
--- a/collects/mrlib/cache-image-snip.ss
+++ b/collects/mrlib/cache-image-snip.ss
@@ -147,7 +147,9 @@
                                       void
                                       (lambda (x) #f))])
           (if data
-              (argb->cache-image-snip (make-argb (first data) (second data)) (third data) (fourth data))
+              (argb->cache-image-snip (make-argb (first data) (second data))
+                                      (third data)
+                                      (fourth data))
               (make-null-cache-image-snip))))
       (super-new)))
   
@@ -634,9 +636,16 @@ for b3, we have:
               (* -255 m3))
            (- 255 m3))))
 
+  (define bitmap-size/c (and/c integer? exact? (between/c 1 10000)))
+  
   (provide/contract
-   [overlay-bitmap (argb? number? number? (is-a?/c bitmap%) (is-a?/c bitmap%) . -> . any)]
-   [build-bitmap (((is-a?/c dc<%>) . -> . any) number? number? . -> . (is-a?/c bitmap%))]
+   [overlay-bitmap (argb? (and/c integer? exact?)
+                          (and/c integer? exact?)
+                          (is-a?/c bitmap%)
+                          (is-a?/c bitmap%)
+                          . -> .
+                          any)]
+   [build-bitmap (((is-a?/c dc<%>) . -> . any) bitmap-size/c bitmap-size/c . -> . (is-a?/c bitmap%))]
    [flatten-bitmap ((is-a?/c bitmap%) . -> . (is-a?/c bitmap%))]
 
    [argb->cache-image-snip (argb? number? number? . -> . (is-a?/c cache-image-snip%))]