scrolling

2 files changed, 30 insertions, 0 deletions

diff --git a/src/libdraw/mkfile b/src/libdraw/mkfile
index e734fd5f..fbbe68e4 100644
--- a/src/libdraw/mkfile
+++ b/src/libdraw/mkfile
@@ -42,6 +42,7 @@ OFILES=\
 	rectclip.$O\
 	replclipr.$O\
 	rgb.$O\
+	scroll.$O\
 	string.$O\
 	stringbg.$O\
 	stringsubfont.$O\
diff --git a/src/libdraw/scroll.c b/src/libdraw/scroll.c
new file mode 100644
index 00000000..ea0aa25c
--- /dev/null
+++ b/src/libdraw/scroll.c
@@ -0,0 +1,29 @@
+#include <u.h>
+#include <libc.h>
+#include <draw.h>
+
+int
+mousescrollsize(int maxlines)
+{
+	static int lines, pcnt;
+	char *mss;
+
+	if(lines == 0 && pcnt == 0){
+		mss = getenv("mousescrollsize");
+		if(mss){
+			if(strchr(mss, '%') != nil)
+				pcnt = atof(mss);
+			else
+				lines = atoi(mss);
+			free(mss);
+		}
+		if(lines == 0 && pcnt == 0)
+			lines = 1;
+		if(pcnt>=100)
+			pcnt = 100;
+	}
+
+	if(lines)
+		return lines;
+	return pcnt * maxlines/100.0;	
+}