Windows DPI awareness

.winres/winres.json

@@ -0,0 +1,54 @@
+{
+  "RT_GROUP_ICON": {
+    "APP": {
+      "0000": [
+        "icon.png"
+      ]
+    }
+  },
+  "RT_MANIFEST": {
+    "#1": {
+      "0409": {
+        "identity": {},
+        "description": "",
+        "minimum-os": "win7",
+        "execution-level": "",
+        "ui-access": false,
+        "auto-elevate": false,
+        "dpi-aware": "true/pm",
+        "dpi-awareness": "per monitor v2",
+        "disable-theming": false,
+        "disable-window-filtering": false,
+        "high-resolution-scrolling-aware": false,
+        "ultra-high-resolution-scrolling-aware": false,
+        "long-path-aware": false,
+        "printer-driver-isolation": false,
+        "gdi-scaling": false,
+        "segment-heap": false,
+        "use-common-controls-v6": true
+      }
+    }
+  },
+  "RT_VERSION": {
+    "#1": {
+      "0000": {
+        "info": {
+          "0409": {
+            "Comments": "",
+            "CompanyName": "",
+            "FileDescription": "",
+            "FileVersion": "",
+            "InternalName": "",
+            "LegalCopyright": "",
+            "LegalTrademarks": "",
+            "OriginalFilename": "",
+            "PrivateBuild": "",
+            "ProductName": "",
+            "ProductVersion": "",
+            "SpecialBuild": ""
+          }
+        }
+      }
+    }
+  }
+}

README.md

@@ -1 +1,21 @@
-# nterm
+# nTerm
+
+## Developer Notes
+
+To build without a CLI showing on Windows build with: `go build -ldflags -H=windowsgui .`.
+
+### OS Manifests
+
+To ensure we get proper configuration on each OS, we sometimes need extra files that are part of the compilation.
+This ensures we do get things like icons and proper DPI awareness (which is important for crisp text).
+
+Those manifests are turned into files (e.g. `*.syso`) that get detected and used by `go build` automatically.
+
+#### Windows
+
+The Windows manifest and icon are placed inside the `.winres` folder, which gets compiled into the required
+`*.syso` files by running `go-winres make --in ./.winres/winres.json`.
+
+`go-winres` can be installed using `go install github.com/tc-hib/go-winres@latest`.
+
+**Note:** Any changes to things in `.winres` requires re-running the `go-winres` command and then recompiling the Go program.

main.go

@@ -115,6 +115,9 @@ const (
 
 	// How many lines to move per scroll
 	defaultScrollSpd = 1
+
+	unscaledWindowWidth  = 1280
+	unscaledWindowHeight = 720
 )
 
 var (
@@ -137,8 +140,11 @@ func main() {
 		panic("Failed to init engine. Err: " + err.Error())
 	}
 
+	// This scaling lets us respect the user's request for zoomed-in programs
+	dpiScaling := getDpiScaling()
+
 	rend := rend3dgl.NewRend3DGL()
-	win, err := engine.CreateOpenGLWindowCentered("nTerm", 1280, 720, engine.WindowFlags_ALLOW_HIGHDPI|engine.WindowFlags_RESIZABLE, rend)
+	win, err := engine.CreateOpenGLWindowCentered("nTerm", int32(unscaledWindowWidth*dpiScaling), int32(unscaledWindowHeight*dpiScaling), engine.WindowFlags_ALLOW_HIGHDPI|engine.WindowFlags_RESIZABLE, rend)
 	if err != nil {
 		panic("Failed to create window. Err: " + err.Error())
 	}
@@ -197,6 +203,40 @@ func main() {
 	}
 }
 
+func getDpiScaling() float32 {
+
+	// Great read on DPI here: https://nlguillemot.wordpress.com/2016/12/11/high-dpi-rendering/
+
+	// The no-scaling DPI on different platforms (e.g. when scale=100% on windows)
+	var defaultDpi float32 = 96
+	if runtime.GOOS == "windows" {
+		defaultDpi = 96
+	} else if runtime.GOOS == "darwin" {
+		defaultDpi = 72
+	}
+
+	// Current DPI of the monitor
+	_, dpiHorizontal, _, err := sdl.GetDisplayDPI(0)
+	if err != nil {
+		dpiHorizontal = defaultDpi
+		fmt.Printf("Failed to get DPI with error '%s'. Using default DPI of '%f'\n", err.Error(), defaultDpi)
+	}
+
+	// Scaling factor (e.g. will be 1.25 for 125% scaling on windows)
+	dpiScaling := dpiHorizontal / defaultDpi
+
+	fmt.Printf(
+		"Default DPI=%f\nHorizontal DPI=%f\nDPI scaling=%f\nUnscaled window size (width, height)=(%d, %d)\nScaled window size (width, height)=(%d, %d)\n\n",
+		defaultDpi,
+		dpiHorizontal,
+		dpiScaling,
+		unscaledWindowWidth, unscaledWindowHeight,
+		int32(unscaledWindowWidth*dpiScaling), int32(unscaledWindowHeight*dpiScaling),
+	)
+
+	return dpiScaling
+}
+
 func (nt *nterm) handleSDLEvent(e sdl.Event) {
 
 	switch e := e.(type) {