Merge image_merge into 4902-image-support

Replace SIXEL retention and the per-client cache with the global indexed-image cache from image_merge. Adapt its backend callbacks for Kitty and test palette quantization through both input protocols.

regress/image-sixel-cache.sh

@@ -0,0 +1,78 @@
+#!/bin/sh
+
+# Check that cached colours and dithering survive clipping and client changes,
+# and that a visible crop is drawn when the whole scaled image is too large.
+
+PATH=/bin:/usr/bin
+TERM=screen
+export TERM
+[ -z "$TEST_TMUX" ] && TEST_TMUX=$(readlink -f ../tmux)
+
+python3 -B - "$TEST_TMUX" <<'PY'
+import sys
+from image_test import image_test, sixel, check_image
+
+levels = [0, 14, 29, 43, 57, 71, 86, 100]
+palette = [(r, g, b) for r in levels for g in levels for b in levels]
+wire = sixel(32, 16, palette, list(range(512)))
+
+with image_test(sys.argv[1]) as test:
+    first = test.attach()
+    test.emit(wire)
+    original = first.images()
+    assert len(original) == 1 and original[0][:2] == (32, 16)
+
+    # Clients with the same cell size draw identical indexed pixels.
+    second = test.attach()
+    test.redraw()
+    assert first.images() == second.images() == original
+
+    # A different cell size must not replace the first clients' result.
+    small = test.attach(cw=4, ch=8)
+    test.redraw()
+    scaled = small.images()
+    assert len(scaled) == 1 and scaled[0][:2] == (16, 8)
+    assert first.images() == second.images() == original
+
+    # Overwrite the first cell. The remaining pixels retain the full palette
+    # and dithering, rather than converting the smaller rectangle again.
+    test.emit(b'\033[HX')
+    expected = [original[0][2][y * 32 + x]
+        for y in range(16) for x in range(8, 32)]
+    for client in (first, second):
+        images = client.images()
+        assert len(images) == 1
+        check_image(images[0], 24, 16, expected)
+    small_expected = [scaled[0][2][y * 16 + x]
+        for y in range(8) for x in range(4, 16)]
+    images = small.images()
+    assert len(images) == 1
+    check_image(images[0], 12, 8, small_expected)
+
+    # Changing back to an earlier cell size reuses the same indexed pixels.
+    test.resize(small, 40, 16)
+    test.redraw()
+    for client in (first, second, small):
+        images = client.images()
+        assert len(images) == 1
+        check_image(images[0], 24, 16, expected)
+
+    # Replacing the source must not draw pixels from the deleted image.
+    test.emit(b'\033[2J\033[H' +
+        sixel(8, 16, [(100, 0, 0)], [0] * (8 * 16)))
+    for client in (first, second, small):
+        images = client.images()
+        assert len(images) == 1
+        check_image(images[0], 8, 16, [(255, 0, 0)] * (8 * 16))
+
+with image_test(sys.argv[1], sx=1) as test:
+    client = test.attach()
+    test.emit(sixel(16, 16, [(100, 0, 0)], [0] * (16 * 16)))
+    # The whole image would be 12000 pixels wide, beyond the SIXEL limit.
+    # Its visible first cell is still valid and must be converted directly.
+    test.resize(client, 1, 16, cw=6000, ch=16)
+    test.redraw()
+    images = client.images()
+    assert len(images) == 1
+    check_image(images[0], 6000, 16, [(255, 0, 0)] * (6000 * 16))
+PY

regress/image-sixel-palette.sh

@@ -18,28 +18,23 @@ palette = [(r, g, b) for r in levels for g in levels for b in levels]
 expected = [tuple((c * 255 + 50) // 100 for c in p) for p in palette]
 with image_test(sys.argv[1]) as test:
     client = test.attach()
-    test.emit(sixel(32, 16, palette, list(range(512))))
-    images = client.images()
-    assert len(images) == 1 and images[0][:2] == (32, 16)
-    assert images[0][2] == expected, 'original SIXEL palette changed'
-    test.redraw()
-    assert client.images() == images, 'retained palette changed on redraw'
-
-    # Kitty input exercises RGBA quantization rather than SIXEL retention.
     rgba = bytes(c for pixel in expected for c in (*pixel, 255))
-    test.emit(b'\033[2J\033[H\033_Ga=T,q=2,f=32,s=32,v=16;' +
+    kitty = (b'\033_Ga=T,q=2,f=32,s=32,v=16;' +
         base64.b64encode(rgba) + b'\033\\')
-    images = client.images()
-    assert len(images) == 1 and images[0][:2] == (32, 16)
-    actual = images[0][2]
-    assert all(c is not None for c in actual), 'dithering introduced holes'
-    assert 128 <= len(set(actual)) <= 256, len(set(actual))
-    errors = [abs(a - e) for p, q in zip(actual, expected) for a, e in zip(p, q)]
-    assert max(errors) <= 80, max(errors)
-    assert sum(errors) / len(errors) <= 16, sum(errors) / len(errors)
-    assert max(actual[0]) <= 30 and min(actual[-1]) >= 225, (
-        'black/white extremes lost', actual[0], actual[-1])
-    for _ in range(3):
-        test.redraw()
-        assert client.images() == images, 'palette or dithering changed on redraw'
+    # Both input protocols use the shared RGBA model and quantization.
+    for wire in (sixel(32, 16, palette, list(range(512))), kitty):
+        test.emit(b'\033[2J\033[H' + wire)
+        images = client.images()
+        assert len(images) == 1 and images[0][:2] == (32, 16)
+        actual = images[0][2]
+        assert all(c is not None for c in actual), 'dithering introduced holes'
+        assert 128 <= len(set(actual)) <= 256, len(set(actual))
+        errors = [abs(a - e) for p, q in zip(actual, expected) for a, e in zip(p, q)]
+        assert max(errors) <= 80, max(errors)
+        assert sum(errors) / len(errors) <= 16, sum(errors) / len(errors)
+        assert max(actual[0]) <= 30 and min(actual[-1]) >= 225, (
+            'black/white extremes lost', actual[0], actual[-1])
+        for _ in range(3):
+            test.redraw()
+            assert client.images() == images, 'palette or dithering changed on redraw'
 PY

regress/image-sixel-parse.sh

@@ -31,7 +31,7 @@ with image_test(sys.argv[1]) as test:
         assert len(client.images()) == 1
         check_image(client.images()[0], 8, 16, [rgb] * (8 * 16))
 
-    # Undefined registers are black in the shared model and in retained output.
+    # Undefined registers are black in the shared image model.
     test.emit(b'\033[2J\033[H\033P9;1q"1;1;8;16'
         b'#5!8~-!8~-!8N\033\\')
     assert len(client.images()) == 1