Add dpi params: fontOversampleH / fontOversampleV + add hello_imgui_e…

…xample.ini

hello_imgui_example.ini

@@ -0,0 +1,58 @@
+; This is an example configuration file for hello_imgui
+; To use it:
+; - Rename this file to hello_imgui.ini
+; - Edit the values to match your needs
+; - Place it in the current working directory of your application
+; - Or any parent directory of the current working directory, to apply the settings to multiple applications.
+
+
+
+[DpiAwareParams]
+; - `dpiWindowSizeFactor`:factor by which window size should be multiplied
+; - `fontRenderingScale`:
+;    factor by which fonts glyphs should be scaled at rendering time
+;    (typically 1 on windows, and 0.5 on macOS retina screens)
+;
+; By default, Hello ImGui will compute them automatically
+;dpiWindowSizeFactor=2
+;fontRenderingScale=0.5
+
+
+; `fontOversampleH` and `fontOversampleV` : Font oversampling parameters
+; Rasterize at higher quality for sub-pixel positioning. Probably unused if freeType is used.
+; If not zero, these values will be used to set the oversampling factor when loading fonts.
+; (i.e. they will be set in ImFontConfig::OversampleH and ImFontConfig::OversampleV)
+; fontOversampleH: The difference between 2 and 3 for OversampleH is minimal.
+;              You can reduce this to 1 for large glyphs save memory.
+; fontOversampleV: This is not really useful as we don't use sub-pixel positions on the Y axis.
+; fontOversampleH=2
+; fontOversampleV=1
+
+
+
+[OpenGlOptions]
+; OpenGlOptions contains advanced options used at the startup of OpenGL.
+; These parameters are reserved for advanced users.
+; By default, Hello ImGui will select reasonable default values, and these parameters are not used.
+; Use at your own risk, as they make break the multi-platform compatibility of your application!
+; All these parameters are platform dependent.
+; For real multiplatform examples, see
+;     hello_imgui/src/hello_imgui/internal/backend_impls/opengl_setup_helper/opengl_setup_glfw.cpp
+; and
+;     hello_imgui/src/hello_imgui/internal/backend_impls/opengl_setup_helper/opengl_setup_sdl.cpp
+
+; GlslVersion = 130
+; MajorVersion = 3
+; MinorVersion = 2
+; UseCoreProfile = true
+; UseForwardCompat = false
+
+;  `AntiAliasingSamples`
+;  If not zero, this value will be used to reduce the number of samples used for anti-aliasing.
+;  This is used only when running with Glfw  + OpenGL (which is the default)
+;  Notes:
+;  - by default, we query the maximum number of samples supported by the hardwareand we use this value
+;  - if you set this value to a non-zero value, it will be used instead of the maximum value
+;    (except if it is greater than the maximum value, in which case a warning will be issued)
+;  (it will be via `glfwWindowHint(GLFW_SAMPLES, AntiAliasingSamples);`)
+; AntiAliasingSamples=16

src/hello_imgui/dpi_aware.h

@@ -7,8 +7,9 @@ namespace HelloImGui
 
 //
 // Hello ImGui will try its best to automatically handle DPI scaling for you.
-// It does this by setting two values:
 //
+// Parameters to change the scaling behavior:
+// ------------------------------------------
 // - `dpiWindowSizeFactor`:
 //        factor by which window size should be multiplied
 //
@@ -19,22 +20,22 @@ namespace HelloImGui
 //    By default, Hello ImGui will compute them automatically,
 //    when dpiWindowSizeFactor and fontRenderingScale are set to 0.
 //
+// Parameters to improve font rendering quality:
+// ---------------------------------------------
+// - `fontOversampleH` and `fontOversampleV` : Font oversampling parameters
+//     Rasterize at higher quality for sub-pixel positioning. Probably unused if freeType is used.
+//     If not zero, these values will be used to set the oversampling factor when loading fonts.
+//
+//
 // How to set those values manually:
 // ---------------------------------
 // If it fails (i.e. your window and/or fonts are too big or too small),
 // you may set them manually:
 //    (1) Either by setting them programmatically in your application
 //        (set their values in `runnerParams.dpiAwareParams`)
-//    (2) Either by setting them in a `hello_imgui.ini` file in the current folder, or any of its parent folders.
-//       (this is useful when you want to set them for a specific app or set of apps, without modifying the app code)
+//    (2) Either by setting them in a `hello_imgui.ini` file. See hello_imgui/hello_imgui_example.ini for more info
 // Note: if several methods are used, the order of priority is (1) > (2)
 //
-// Example content of a ini file:
-// ------------------------------
-//     [DpiAwareParams]
-//     dpiWindowSizeFactor=2
-//     fontRenderingScale=0.5
-//
 // For more information, see the documentation on DPI handling, here: https://pthom.github.io/hello_imgui/book/doc_api.html#handling-screens-with-high-dpi
 //
 struct DpiAwareParams
@@ -68,10 +69,22 @@ struct DpiAwareParams
     // (This parameter will be used to set ImGui::GetIO().FontGlobalScale at startup)
     float fontRenderingScale = 0.0f;
 
-	// `onlyUseFontDpiResponsive`
-	// If true, guarantees that only HelloImGui::LoadDpiResponsiveFont will be used to load fonts.
-	// (also for the default font)
-	bool onlyUseFontDpiResponsive = false;
+    // `onlyUseFontDpiResponsive`
+    // If true, guarantees that only HelloImGui::LoadDpiResponsiveFont will be used to load fonts.
+    // (also for the default font)
+    bool onlyUseFontDpiResponsive = false;
+
+    // `fontOversampleH` and `fontOversampleV` : Font oversampling parameters
+    // Rasterize at higher quality for sub-pixel positioning. Probably unused if freeType is used.
+    // If not zero, these values will be used to set the oversampling factor when loading fonts.
+    // (i.e. they will be set in ImFontConfig::OversampleH and ImFontConfig::OversampleV)
+    // OversampleH: The difference between 2 and 3 for OversampleH is minimal.
+    //              You can reduce this to 1 for large glyphs save memory.
+    // OversampleV: This is not really useful as we don't use sub-pixel positions on the Y axis.
+    // Read https://github.com/nothings/stb/blob/master/tests/oversample/README.md for details.
+    int             fontOversampleH = 0;  // Default is 2 in ImFontConfig
+    int             fontOversampleV = 0;  // Default is 1 in ImFontConfig
+
 
     // `dpiFontLoadingFactor`
     //     factor by which font size should be multiplied at loading time to get a similar

src/hello_imgui/impl/hello_imgui_font.cpp

@@ -128,6 +128,15 @@ namespace HelloImGui
 
         FontLoadingParams params = params_;
 
+        // Font oversampling (set by dpiAwareParams)
+        {
+            const auto& dpiAwareParams = HelloImGui::GetRunnerParams()->dpiAwareParams;
+            if (dpiAwareParams.fontOversampleH > 0)
+                params.fontConfig.OversampleH = dpiAwareParams.fontOversampleH;
+            if (dpiAwareParams.fontOversampleV > 0)
+                params.fontConfig.OversampleV = dpiAwareParams.fontOversampleV;
+        }
+
         float fontSize = fontSize_;
         if (params.adjustSizeToDpi)
             fontSize *= HelloImGui::DpiFontLoadingFactor();
@@ -271,7 +280,7 @@ namespace HelloImGui
 	}
 
 
-	ImFont* LoadFontTTF(const std::string & fontFilename, float fontSize, bool useFullGlyphRange, ImFontConfig config)
+    ImFont* LoadFontTTF(const std::string & fontFilename, float fontSize, bool useFullGlyphRange, ImFontConfig config)
     {
         FontLoadingParams fontLoadingParams;
         if (useFullGlyphRange)

src/hello_imgui/internal/backend_impls/abstract_runner.cpp

@@ -344,7 +344,19 @@ void ReadDpiAwareParams(DpiAwareParams* dpiAwareParams)
         auto fontRenderingScale = HelloImGuiIniAnyParentFolder::readFloatValue("DpiAwareParams", "fontRenderingScale");
         if (fontRenderingScale.has_value())
             dpiAwareParams->fontRenderingScale = fontRenderingScale.value();
+    }
 
+    if (dpiAwareParams->fontOversampleH == 0)
+    {
+        auto fontOversampleH = HelloImGuiIniAnyParentFolder::readIntValue("DpiAwareParams", "fontOversampleH");
+        if (fontOversampleH.has_value())
+            dpiAwareParams->fontOversampleH = fontOversampleH.value();
+    }
+    if (dpiAwareParams->fontOversampleV == 0)
+    {
+        auto fontOversampleV = HelloImGuiIniAnyParentFolder::readIntValue("DpiAwareParams", "fontOversampleV");
+        if (fontOversampleV.has_value())
+            dpiAwareParams->fontOversampleV = fontOversampleV.value();
     }
 }