I recently started work on a game project, and decided to use GLFW for windowing / OpenGL context handling. GLFW doesn't have support for creating message boxes / dialogs, and I was unable to find anything simple online to do the job, so I decided to take a shot at creating a library to do so.
I've completed a first iteration of the library (which I'm calling 'Boxer') that supports the creation of message boxes on OS X, Windows, and Linux (with GTK+). I've never released any code intended for reuse, and I'd love to get some feedback, specifically in C++ / library best practices.
There are four files: the header file and an implementation file for each OS. Everything is set up to be built with CMake.
The project is available on my GitHub.
boxer.h
#ifndef BOXER_H
#define BOXER_H
namespace boxer {
enum class Style {
Info,
Warning,
Error,
Question
};
enum class Buttons {
OK,
OKCancel,
YesNo
};
enum class Selection {
OK,
Cancel,
Yes,
No,
None
};
const Style DEFAULT_STYLE = Style::Info;
const Buttons DEFAULT_BUTTONS = Buttons::OK;
Selection show(const char *message, const char *title, Style style, Buttons buttons);
inline Selection show(const char *message, const char *title, Style style) {
return show(message, title, style, DEFAULT_BUTTONS);
}
inline Selection show(const char *message, const char *title, Buttons buttons) {
return show(message, title, DEFAULT_STYLE, buttons);
}
inline Selection show(const char *message, const char *title) {
return show(message, title, DEFAULT_STYLE, DEFAULT_BUTTONS);
}
} // namespace boxer
#endif
boxer_linux.cpp
#include <boxer/boxer.h>
#include <gtk/gtk.h>
namespace boxer {
namespace {
GtkMessageType getMessageType(Style style) {
switch (style) {
case Style::Info:
return GTK_MESSAGE_INFO;
case Style::Warning:
return GTK_MESSAGE_WARNING;
case Style::Error:
return GTK_MESSAGE_ERROR;
case Style::Question:
return GTK_MESSAGE_QUESTION;
default:
return GTK_MESSAGE_INFO;
}
}
GtkButtonsType getButtonsType(Buttons buttons) {
switch (buttons) {
case Buttons::OK:
return GTK_BUTTONS_OK;
case Buttons::OKCancel:
return GTK_BUTTONS_OK_CANCEL;
case Buttons::YesNo:
return GTK_BUTTONS_YES_NO;
default:
return GTK_BUTTONS_OK;
}
}
Selection getSelection(gint response) {
switch (response) {
case GTK_RESPONSE_OK:
return Selection::OK;
case GTK_RESPONSE_CANCEL:
return Selection::Cancel;
case GTK_RESPONSE_YES:
return Selection::Yes;
case GTK_RESPONSE_NO:
return Selection::No;
default:
return Selection::None;
}
}
} // namespace
Selection show(const char *message, const char *title, Style style, Buttons buttons) {
if (!gtk_init_check(0, NULL)) {
return Selection::None;
}
GtkWidget *dialog = gtk_message_dialog_new(NULL,
GTK_DIALOG_MODAL,
getMessageType(style),
getButtonsType(buttons),
"%s",
message);
gtk_window_set_title(GTK_WINDOW(dialog), title);
Selection selection = getSelection(gtk_dialog_run(GTK_DIALOG(dialog)));
gtk_widget_destroy(GTK_WIDGET(dialog));
while (g_main_context_iteration(NULL, false));
return selection;
}
} // namespace boxer
boxer_osx.mm
#include <boxer/boxer.h>
#import <Cocoa/Cocoa.h>
namespace boxer {
namespace {
NSString* const OK_STR = @"OK";
NSString* const CANCEL_STR = @"Cancel";
NSString* const YES_STR = @"Yes";
NSString* const NO_STR = @"No";
NSAlertStyle getAlertStyle(Style style) {
switch (style) {
case Style::Info:
return NSInformationalAlertStyle;
case Style::Warning:
return NSWarningAlertStyle;
case Style::Error:
return NSCriticalAlertStyle;
case Style::Question:
return NSWarningAlertStyle;
default:
return NSInformationalAlertStyle;
}
}
void setButtons(NSAlert *alert, Buttons buttons) {
switch (buttons) {
case Buttons::OK:
[alert addButtonWithTitle:OK_STR];
break;
case Buttons::OKCancel:
[alert addButtonWithTitle:OK_STR];
[alert addButtonWithTitle:CANCEL_STR];
break;
case Buttons::YesNo:
[alert addButtonWithTitle:YES_STR];
[alert addButtonWithTitle:NO_STR];
break;
default:
[alert addButtonWithTitle:OK_STR];
}
}
Selection getSelection(int index, Buttons buttons) {
switch (buttons) {
case Buttons::OK:
return index == NSAlertFirstButtonReturn ? Selection::OK : Selection::None;
case Buttons::OKCancel:
if (index == NSAlertFirstButtonReturn) {
return Selection::OK;
} else if (index == NSAlertSecondButtonReturn) {
return Selection::Cancel;
} else {
return Selection::None;
}
case Buttons::YesNo:
if (index == NSAlertFirstButtonReturn) {
return Selection::Yes;
} else if (index == NSAlertSecondButtonReturn) {
return Selection::No;
} else {
return Selection::None;
}
default:
return Selection::None;
}
}
} // namespace
Selection show(const char *message, const char *title, Style style, Buttons buttons) {
NSAlert *alert = [[NSAlert alloc] init];
[alert setMessageText:[NSString stringWithCString:title
encoding:[NSString defaultCStringEncoding]]];
[alert setInformativeText:[NSString stringWithCString:message
encoding:[NSString defaultCStringEncoding]]];
[alert setAlertStyle:getAlertStyle(style)];
setButtons(alert, buttons);
Selection selection = getSelection([alert runModal], buttons);
[alert release];
return selection;
}
} // namespace boxer
boxer_win.cpp
#include <boxer/boxer.h>
#include <windows.h>
namespace boxer {
namespace {
UINT getIcon(Style style) {
switch (style) {
case Style::Info:
return MB_ICONINFORMATION;
case Style::Warning:
return MB_ICONWARNING;
case Style::Error:
return MB_ICONERROR;
case Style::Question:
return MB_ICONQUESTION;
default:
return MB_ICONINFORMATION;
}
}
UINT getButtons(Buttons buttons) {
switch (buttons) {
case Buttons::OK:
return MB_OK;
case Buttons::OKCancel:
return MB_OKCANCEL;
case Buttons::YesNo:
return MB_YESNO;
default:
return MB_OK;
}
}
Selection getSelection(int response) {
switch (response) {
case IDOK:
return Selection::OK;
case IDCANCEL:
return Selection::Cancel;
case IDYES:
return Selection::Yes;
case IDNO:
return Selection::No;
default:
return Selection::None;
}
}
} // namespace
Selection show(const char *message, const char *title, Style style, Buttons buttons) {
UINT flags = MB_TASKMODAL;
flags |= getIcon(style);
flags |= getButtons(buttons);
return getSelection(MessageBox(NULL, message, title, flags));
}
} // namespace boxer
Example
Here is an example program that uses Boxer:
#include <boxer/boxer.h>
int main(int argc, char *argv[]) {
boxer::show("Simple message boxes are very easy to create.", "Simple Example");
boxer::show("There are a few different message box styles to choose from.", "Style Example", boxer::Style::Error);
boxer::Selection selection;
do {
selection = boxer::show("Different buttons may be used, and the user's selection can be checked. Would you like to see this message again?", "Selection Example", boxer::Style::Question, boxer::Buttons::YesNo);
} while (selection == boxer::Selection::Yes);
return 0;
}
