Fix compiler warnings (-Wformat-truncation=)

gcc warnings:

    src/viewer/scrollview.cpp:404:31: warning: ‘%s’ directive output may be
        truncated writing up to 4095 bytes into a region of size between 4084 and 4093 [-Wformat-truncation=]
    src/viewer/scrollview.cpp:572:31: warning: ‘%s’ directive output may be
        truncated writing up to 4095 bytes into a region of size between 4084 and 4093 [-Wformat-truncation=]

Signed-off-by: Stefan Weil <[email protected]>

Author: stweil

src/viewer/scrollview.cpp

@@ -394,14 +394,14 @@ void ScrollView::SendMsg(const char* format, ...) {
   if (!points_->empty)
     SendPolygon();
   va_list args;
-  char message[kMaxMsgSize];
+  char message[kMaxMsgSize - 4];
 
   va_start(args, format);  // variable list
-  vsnprintf(message, kMaxMsgSize, format, args);
+  vsnprintf(message, sizeof(message), format, args);
   va_end(args);
 
   char form[kMaxMsgSize];
-  snprintf(form, kMaxMsgSize, "w%u:%s\n", window_id_, message);
+  snprintf(form, sizeof(form), "w%u:%s\n", window_id_, message);
 
   stream_->Send(form);
 }
@@ -562,14 +562,14 @@ void ScrollView::AlwaysOnTop(bool b) {
 // Adds a message entry to the message box.
 void ScrollView::AddMessage(const char* format, ...) {
   va_list args;
-  char message[kMaxMsgSize];
-  char form[kMaxMsgSize];
+  char message[kMaxMsgSize - 4];
 
   va_start(args, format);  // variable list
-  vsnprintf(message, kMaxMsgSize, format, args);
+  vsnprintf(message, sizeof(message), format, args);
   va_end(args);
 
-  snprintf(form, kMaxMsgSize, "w%u:%s", window_id_, message);
+  char form[kMaxMsgSize];
+  snprintf(form, sizeof(form), "w%u:%s", window_id_, message);
 
   char* esc = AddEscapeChars(form);
   SendMsg("addMessage(\"%s\")", esc);