Handle images whose first frame is smaller than the canvas

kittens/tui/images.py

@@ -15,6 +15,7 @@ from typing import (
     Sequence, Tuple, Union
 )
 
+from kitty.fast_data_types import create_canvas
 from kitty.typing import (
     CompletedProcess, GRT_a, GRT_d, GRT_f, GRT_m, GRT_o, GRT_t, HandlerType
 )
@@ -145,7 +146,7 @@ def identify(path: str) -> ImageData:
         if f.mode == 'rgba':
             mode = 'rgba'
             break
-    return ImageData(first['fmt'].lower(), frames[0].width, frames[0].height, mode, frames)
+    return ImageData(first['fmt'].lower(), frames[0].canvas_width, frames[0].canvas_height, mode, frames)
 
 
 class RenderedImage(ImageData):
@@ -232,6 +233,14 @@ def render_image(
             f.path = output_prefix + f'-{index}.{m.mode}'
             os.rename(os.path.join(tdir, x), f.path)
             check_resize(f)
+    f = ans.frames[0]
+    if f.width != ans.width or f.height != ans.height:
+        with open(f.path, 'r+b') as ff:
+            data = ff.read()
+            ff.seek(0)
+            ff.truncate()
+            cd = create_canvas(data, f.width, f.canvas_x, f.canvas_y, ans.width, ans.height, 3 if ans.mode == 'rgb' else 4)
+            ff.write(cd)
     if unseen:
         raise ConvertFailed(path, f'Failed to render {len(unseen)} out of {len(m)} frames of animation')
 

kitty/fast_data_types.pyi

@@ -634,6 +634,9 @@ def patch_color_profiles(
     pass
 
 
+def create_canvas(d: bytes, w: int, x: int, y: int, cw: int, ch: int, bpp: int) -> bytes: ...
+
+
 def os_window_font_size(
     os_window_id: int, new_sz: float = -1., force: bool = False
 ) -> float:

kitty/graphics.c

@@ -1640,9 +1640,35 @@ PyTypeObject GraphicsManager_Type = {
     .tp_members = members,
 };
 
+static PyObject*
+pycreate_canvas(PyObject *self UNUSED, PyObject *args) {
+    unsigned int bytes_per_pixel;
+    unsigned int over_width, width, height, x, y;
+    Py_ssize_t over_sz;
+    const uint8_t *over_data;
+    if (!PyArg_ParseTuple(args, "y#IIIIII", &over_data, &over_sz, &over_width, &x, &y, &width, &height, &bytes_per_pixel)) return NULL;
+    size_t canvas_sz = width * height * bytes_per_pixel;
+    PyObject *ans = PyBytes_FromStringAndSize(NULL, canvas_sz);
+    if (!ans) return NULL;
+
+    uint8_t* canvas = (uint8_t*)PyBytes_AS_STRING(ans);
+    memset(canvas, 0, canvas_sz);
+    ComposeData cd = {
+        .needs_blending = bytes_per_pixel == 4,
+        .over_width = over_width, .over_height = over_sz / (bytes_per_pixel * over_width),
+        .under_width = width, .under_height = height,
+        .over_px_sz = bytes_per_pixel, .under_px_sz = bytes_per_pixel,
+        .over_offset_x = x, .over_offset_y = y
+    };
+    compose(cd, canvas, over_data);
+
+    return ans;
+}
+
 static PyMethodDef module_methods[] = {
     M(shm_write, METH_VARARGS),
     M(shm_unlink, METH_VARARGS),
+    M(create_canvas, METH_VARARGS),
     {NULL, NULL, 0, NULL}        /* Sentinel */
 };