app/gui: support HiDPI on macOS #3248
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KhoraLee
changed the title
| @@ -319,10 +319,18 @@ bool init(EmuEnvState &state, Config &cfg, const Root &root_paths) { | |||
| window_type |= SDL_WINDOW_ALLOW_HIGHDPI; | |||
| state.dpi_scale = ddpi / 96; | |||
| } | |||
| #elif defined(__APPLE__) | |||
| window_type |= SDL_WINDOW_ALLOW_HIGHDPI; | |||
| state.dpi_scale = 2; // It is fixed value on macOS. | |||
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Does using the windows/linux approach (calling SDL_GetDisplayDPI then dividing it by 96) not return 2?
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macOS's SDL_GetDisplayDPI returns display's real ppi (in my case around 255: 3024x1964 14.2").
| #else | ||
| state.window = WindowPtr(SDL_CreateWindow(window_title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, DEFAULT_RES_WIDTH, DEFAULT_RES_HEIGHT, window_type | SDL_WINDOW_RESIZABLE), SDL_DestroyWindow); | ||
| #endif |
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I think calling SDL_CreateWindow with DEFAULT_RES_WIDTH and DEFAULT_RES_HEIGHT should be the correct behavior on all platforms
| SDL_GetWindowSize(state->window, &w, &h); | ||
| ImGui_ImplSdl_GetDrawableSize(state, display_w, display_h); | ||
| #if __APPLE__ | ||
| // On macOS, if HiDPI is enabled(SDL_WINDOW_ALLOW_HIGHDPI) SDL will create a window that size is 960x544 points. | ||
| // But it is actually 1920x1088 pixels. Since SDL_GetWindowSize returns 960x544 points, we need to multiply by 2. | ||
| w *= 2; | ||
| h *= 2; | ||
| #endif | ||
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SDL_GetWindowSize returns the screen dimensions in coordinates while ImGui_ImplSdl_GetDrawableSize returns the same screen dimension in pixel, this is done because of hidpi scaling. What you are doing is making ImGui believe the dpi scaling is 1.0 which sounds kind of counter-intuitive (and also forces you to implement workarounds like the one below for SDL_GetMouseState)
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But from my windows pc with 150% scale, EmuEnvState's dpi_scale is 1.5 but it's w and display_w is same(960) and h and display is also same(544) so ImGui's DisplayFramebufferScale is set to (1, 1).
Also as screenshot shows it was rendering at real pixel. So I was thinking HiDPI is correctly working.
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Hmm, I'm not entirely sure, but looking at SDL high_dpi stuff. We might actually not care at all about the SDL_WINDOW_ALLOW_HIGHDPI flag. What we could instead is not use this flag and just scale everything using the dpi scale. The result would be the same but not have different behavior on mac and other devices. What setting SDL_WINDOW_ALLOW_HIGHDPI does is make screen coordinates bigger than screen pixels, but we really don't care about that as we use our own renderer and everything. What we care about is just making everything big/sharp enough which we should be able to do only using the dpi_scale variable. |
This PR will enable HiDPI on macOS.
Screenshots