Add dpi-scale config option (#198)

If dpi-scale is set in aminal.toml then this overrides aminal's own
DPI calculation. This is useful for working around unusual monitor
setups or users just who prefer a different DPI scale.

README.md

@@ -114,6 +114,7 @@ shell = "/bin/bash"         # The shell to run for the terminal session. Default
 search_url = "https://www.google.com/search?q=$QUERY" # The search engine to use for the "search selected text" action. Defaults to google. Set this to your own search url using $QUERY as the keywords to replace when searching.
 max_lines = 1000            # Maximum number of lines in the terminal buffer.
 copy_and_paste_with_mouse = true # Text selected with the mouse is copied to the clipboard on end selection, and is pasted on right mouse button click.
+dpi-scale = 0.0             # Override DPI scale. Defaults to 0.0 (let Aminal determine the DPI scale itself).
 
 [colours]
   cursor        = "#e8dfd6" 

config/config.go

@@ -7,14 +7,15 @@ import (
 )
 
 type Config struct {
-	DebugMode    bool             `toml:"debug"`
+	DebugMode             bool             `toml:"debug"`
-	Slomo        bool             `toml:"slomo"`
+	Slomo                 bool             `toml:"slomo"`
-	ColourScheme ColourScheme     `toml:"colours"`
+	ColourScheme          ColourScheme     `toml:"colours"`
-	Shell        string           `toml:"shell"`
+	DPIScale              float32          `toml:"dpi-scale"`
-	KeyMapping   KeyMappingConfig `toml:"keys"`
+	Shell                 string           `toml:"shell"`
-	SearchURL    string           `toml:"search_url"`
+	KeyMapping            KeyMappingConfig `toml:"keys"`
-	MaxLines     uint64           `toml:"max_lines"`
+	SearchURL             string           `toml:"search_url"`
-	CopyAndPasteWithMouse bool    `toml:"copy_and_paste_with_mouse"`
+	MaxLines              uint64           `toml:"max_lines"`
+	CopyAndPasteWithMouse bool             `toml:"copy_and_paste_with_mouse"`
 }
 
 type KeyMappingConfig map[string]string

gui/gui.go

@@ -50,12 +50,12 @@ type GUI struct {
 	arrowCursor       *glfw.Cursor
 	defaultCell       *buffer.Cell
 
-	prevLeftClickX    uint16
+	prevLeftClickX                  uint16
-	prevLeftClickY    uint16
+	prevLeftClickY                  uint16
-	leftClickTime     time.Time
+	leftClickTime                   time.Time
-	leftClickCount    int  // number of clicks in a serie - single click, double click, or triple click
+	leftClickCount                  int // number of clicks in a serie - single click, double click, or triple click
 	mouseMovedAfterSelectionStarted bool
-	internalResize    bool
+	internalResize                  bool
 }
 
 func Min(x, y int) int {
@@ -113,23 +113,32 @@ func (g *GUI) GetMonitor() *glfw.Monitor {
 	return currentMonitor
 }
 
-// RecalculateDpiScale calculates dpi scale in comparison with "standard" monitor's dpi values
+// SetDPIScale sets the GUI DPI scale from user configuration (if set)
-func (g *GUI) RecalculateDpiScale() {
+// or by calculating it from the monitor's configuration and size.
+func (g *GUI) SetDPIScale() {
+	if g.config.DPIScale > 0 {
+		g.dpiScale = g.config.DPIScale
+		return
+	}
+	g.dpiScale = g.calculateDpiScale()
+}
+
+// calculateDpiScale determines the DPI scale in comparison with "standard" monitor's DPI values.
+func (g *GUI) calculateDpiScale() float32 {
 	const standardDpi = 96
 	const mmPerInch = 25.4
+
 	m := g.GetMonitor()
 	widthMM, _ := m.GetPhysicalSize()
-
 	if widthMM == 0 {
-		g.dpiScale = 1.0
+		return 1.0
-	} else {
-		monitorDpi := float32(m.GetVideoMode().Width) / (float32(widthMM) / mmPerInch)
-		g.dpiScale = monitorDpi / standardDpi
 	}
+
+	monitorDpi := float32(m.GetVideoMode().Width) / (float32(widthMM) / mmPerInch)
+	return monitorDpi / standardDpi
 }
 
 func New(config *config.Config, terminal *terminal.Terminal, logger *zap.SugaredLogger) (*GUI, error) {
-
 	shortcuts, err := config.KeyMapping.GenerateActionMap()
 	if err != nil {
 		return nil, err
@@ -293,7 +302,7 @@ func (gui *GUI) Render() error {
 	gui.logger.Debugf("Creating window...")
 	var err error
 	gui.window, err = gui.createWindow()
-	gui.RecalculateDpiScale()
+	gui.SetDPIScale()
 	gui.window.SetSize(int(float32(gui.width)*gui.dpiScale),
 		int(float32(gui.height)*gui.dpiScale))
 	if err != nil {