Real-image posters: blocks while the window is being resized; ARR_TUI_DEBUG_GFX log

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

internal/ui/kitty.go

@@ -7,6 +7,7 @@ import (
 	"image"
 	"image/png"
 	"strings"
+	"time"
 
 	"github.com/gdamore/tcell/v2"
 	"github.com/rivo/tview"
@@ -39,8 +40,24 @@ type kittyGraphics struct {
 	nextID uint32
 	ids    map[footprint]uint32
 	latest map[*image.RGBA]footprint // the footprint of each poster that is currently uploaded
+
+	holdUntil time.Time    // no real images until then (the window is being resized)
+	debug     func(string) // reports what is uploaded, if set
 }
 
+// settleDelay is how long the window size must stay the same before real
+// images are shown again. While a window is dragged to another size, tens of
+// sizes go by; uploading and placing images for each of them races with the
+// terminal's own resizing, and the result can be a placement that does not
+// match the cells (a small poster in a big area, or a corner of a big one).
+const settleDelay = 300 * time.Millisecond
+
+// hold stops real images being drawn until the window has been left alone for settleDelay.
+func (k *kittyGraphics) hold() { k.holdUntil = time.Now().Add(settleDelay) }
+
+// settling reports whether the window size changed so recently that blocks are drawn instead.
+func (k *kittyGraphics) settling() bool { return time.Now().Before(k.holdUntil) }
+
 // footprint identifies an uploaded image: a poster, the part of it that was
 // sent, and the cells it covers.
 type footprint struct {
@@ -112,6 +129,9 @@ func (k *kittyGraphics) show(img *image.RGBA, rect image.Rectangle, cols, rows i
 	}
 	k.ids[key] = id
 	k.latest[img] = key
+	if k.debug != nil {
+		k.debug(fmt.Sprintf("graphics: id %d, poster %dx%d px cropped to %v, placed over %dx%d cells", id, img.Bounds().Dx(), img.Bounds().Dy(), rect, cols, rows))
+	}
 	return id, nil
 }