Improve calculation of terminal size

internal/image/block.go

@@ -9,8 +9,6 @@ import (
 	"os"
 	"runtime"
 	"strings"
-
-	"golang.org/x/term"
 )
 
 const (
@@ -24,16 +22,11 @@ type rgbColor struct {
 }
 
 // writeBlocks resizes the image and outputs it as terminal blocks.
-func writeBlocks(img image.Image) error {
+func writeBlocks(img image.Image, termWidth, termHeight int) error {
 	trueColor := supportsTrueColor()
 
-	termWidth, termHeight, err := term.GetSize(int(os.Stdout.Fd()))
-	if err != nil {
-		return err
-	}
-	cols, rows := imageBlockOutputDimensions(img, termWidth, termHeight)
-
 	// Each terminal block represents 2 vertical pixels.
+	cols, rows := imageBlockOutputDimensions(img, termWidth, termHeight)
 	targetWidth := cols
 	targetHeight := rows * 2
 

internal/image/image.go

@@ -30,23 +30,23 @@ func Render(ctx context.Context, b []byte, nativeOnly bool) error {
 		return nil
 	}
 
-	termWidthPx, termHeightPx, err := getTermSizeInPixels()
+	size, err := getTerminalSize()
 	if err != nil {
 		return err
 	}
-	if termWidthPx == 0 || termHeightPx == 0 {
+	if size.widthPx == 0 || size.heightPx == 0 {
 		// If we're unable to get the terminal dimensions in pixels,
 		// render the image using blocks.
-		return writeBlocks(img)
+		return writeBlocks(img, size.cols, size.rows)
 	}
 
 	switch detectEmulator().Protocol() {
 	case protoInline:
-		return writeInline(img, termWidthPx, termHeightPx)
+		return writeInline(img, size.widthPx, size.heightPx)
 	case protoKitty:
-		return writeKitty(img, termWidthPx, termHeightPx)
+		return writeKitty(img, size.widthPx, size.heightPx)
 	default:
-		return writeBlocks(img)
+		return writeBlocks(img, size.cols, size.rows)
 	}
 }
 
@@ -144,3 +144,10 @@ func convertToRGBA(img image.Image) *image.RGBA {
 		return out
 	}
 }
+
+type terminalSize struct {
+	cols     int
+	rows     int
+	widthPx  int
+	heightPx int
+}

internal/image/term_unix.go

@@ -8,11 +8,16 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-// getTermSizeInPixels returns the size of the terminal in pixels on unix.
-func getTermSizeInPixels() (int, int, error) {
+func getTerminalSize() (terminalSize, error) {
+	var ts terminalSize
 	ws, err := unix.IoctlGetWinsize(int(os.Stdout.Fd()), unix.TIOCGWINSZ)
 	if err != nil {
-		return 0, 0, err
+		return ts, err
 	}
-	return int(ws.Xpixel), int(ws.Ypixel), nil
+
+	ts.cols = int(ws.Col)
+	ts.rows = int(ws.Row)
+	ts.widthPx = int(ws.Xpixel)
+	ts.heightPx = int(ws.Ypixel)
+	return ts, nil
 }

internal/image/term_windows.go

@@ -2,7 +2,23 @@
 
 package image
 
-// getTermSizeInPixels always returns a zero width & height on windows.
-func getTermSizeInPixels() (int, int, error) {
-	return 0, 0, nil
+import (
+	"os"
+
+	"golang.org/x/sys/windows"
+)
+
+func getTerminalSize() (terminalSize, error) {
+	var ts terminalSize
+
+	var info windows.ConsoleScreenBufferInfo
+	handle := windows.Handle(int(os.Stdout.Fd()))
+	err := windows.GetConsoleScreenBufferInfo(handle, &info)
+	if err != nil {
+		return ts, err
+	}
+
+	ts.cols = int(info.Window.Right - info.Window.Left + 1)
+	ts.rows = int(info.Window.Bottom - info.Window.Top + 1)
+	return ts, nil
 }

internal/update/update_windows.go

@@ -247,6 +247,6 @@ func unlockFile(f *os.File) error {
 }
 
 // canReplaceFile always returns true on windows.
-func canReplaceFile(path string) bool {
+func canReplaceFile(_ string) bool {
 	return true
 }