Is SDL_WINDOW_ALLOW_HIGHDPI working on OSX Mojave?

milerius · October 29, 2019, 10:20am

Hello I have a lot of trouble understanding how the DPI scaling with Retina and OSX to adjust my window.

My current retina resolution is: 1680x1050, but I would like to create a 1920x1080 window (my SFML implementation seems to manage retina scaling by default.)

When I create my SDL window it takes the whole window, so I look at the SDL documentation that mentions the flags: SDL_WINDOW_ALLOW_HIGHDPI.

I add this flags when creating the window, but nothing happens, my window is still huge.

I obviously took care to put the flags a true in my plist.info file.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>CFBundleDevelopmentRegion</key>
	<string>English</string>
	<key>CFBundleExecutable</key>
	<string>antara-sdl-example</string>
	<key>CFBundleGetInfoString</key>
	<string></string>
	<key>CFBundleIconFile</key>
	<string>antara-sdl-example</string>
	<key>CFBundleIdentifier</key>
	<string></string>
	<key>CFBundleInfoDictionaryVersion</key>
	<string>6.0</string>
	<key>CFBundleLongVersionString</key>
	<string>0.0.1</string>
	<key>CFBundleName</key>
	<string>antara-sdl-example</string>
	<key>CFBundlePackageType</key>
	<string>APPL</string>
	<key>CFBundleShortVersionString</key>
	<string>0.0.1</string>
	<key>CFBundleSignature</key>
	<string>????</string>
	<key>CFBundleVersion</key>
	<string></string>
	<key>CSResourcesFileMapped</key>
	<true/>
	<key>LSRequiresCarbon</key>
	<true/>
	<key>NSHumanReadableCopyright</key>
	<string></string>
	<key>NSPrincipalClass</key>
    <string>NSApplication</string>
    <key>NSHighResolutionCapable</key>
    <string>true</string>
</dict>
</plist>

I even bothered to create a function in objective c that confirms me that the flags are set to true in the plist file

bool is_high_dpi_capable() noexcept
    {
        NSBundle *bundle = [NSBundle mainBundle];
        if (!bundle)
            return false;
        return bool([bundle objectForInfoDictionaryKey:@"NSHighResolutionCapable"]);
    }

SDL_Window *create_window(entt::registry &registry) noexcept
    {
        auto &canvas_2d = registry.ctx<graphics::canvas_2d>();
        SDL_Window *window = nullptr;
        auto[screen_width, screen_height] = canvas_2d.window.size.to<math::vec2i>(); // 1920x1080 here
        //auto[screen_pos_x, screen_pos_y] = canvas_2d.window.position.to<math::vec2i>();
        if (!core::is_high_dpi_capable()) {
            SDL_LogWarn(SDL_LOG_CATEGORY_SYSTEM, "Your system is not high dpi capable, physical dpi used instead");
        }
        Uint32 flags = SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_ALLOW_HIGHDPI;
        if (canvas_2d.is_fullscreen) {
            flags |= SDL_WINDOW_FULLSCREEN;
        }
        window = SDL_CreateWindow("SDL2 Window", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, screen_width, screen_height, flags);
        return window;
    }

Is there anything I’m doing wrong or not knowing about scaling on OSX?

Current window:

Expected window:

SDL Version : Upstream SDL Compiled Statically for OSX.
Macbook pro: 15.3 inch 2017 OSX Mojave