def render_brush_preview_pixbuf(brushinfo, max_edge_tiles=4):
"""Renders brush preview images
:param lib.brush.BrushInfo brushinfo: settings to render
:param int max_edge_tiles: Use at most this many tiles along an edge
:returns: Preview image, at 128x128 pixels
:rtype: GdkPixbuf
This generates the preview image (128px icon) used for brushes which
don't have saved ones. These include brushes picked from .ORA files
where the parent_brush_name doesn't correspond to a brush in the
user's MyPaint brushes - they're used as the default, and for the
Auto button in the Brush Icon editor.
Brushstrokes are inherently unpredictable in size, so the allowable
area is grown until the brush fits or until the rendering becomes
too big. `max_edge_tiles` limits this growth.
"""
assert max_edge_tiles >= 1
brushinfo = brushinfo.clone() # avoid capturing a ref
brush = Brush(brushinfo)
surface = lib.tiledsurface.Surface()
N = lib.tiledsurface.N
for size_in_tiles in range(1, max_edge_tiles):
width = N * size_in_tiles
height = N * size_in_tiles
surface.clear()
fg, spiral = _brush_preview_bg_fg(surface, size_in_tiles, brushinfo)
brushinfo.set_color_rgb(fg)
brush.reset()
# Curve
shape = _variable_pressure_scribble(width, height, size_in_tiles)
surface.begin_atomic()
for dt, x, y, p, xt, yt in shape:
brush.stroke_to(surface.backend, x, y, p, xt, yt, dt)
surface.end_atomic()
# Check rendered size
tposs = surface.tiledict.keys()
outside = min({tx for tx, ty in tposs}) < 0
outside = outside or (min({ty for tx, ty in tposs}) < 0)
outside = outside or (max({tx for tx, ty in tposs}) >= size_in_tiles)
outside = outside or (max({ty for tx, ty in tposs}) >= size_in_tiles)
if not outside:
break
# Convert to pixbuf at the right scale
rect = (0, 0, width, height)
pixbuf = render_as_pixbuf(surface, *rect, alpha=True)
if max(width, height) != 128:
interp = (GdkPixbuf.InterpType.NEAREST if max(width, height) < 128 else
GdkPixbuf.InterpType.BILINEAR)
pixbuf = pixbuf.scale_simple(128, 128, interp)
# Composite over a checquered bg via Cairo: shows erases
size = gui.style.ALPHA_CHECK_SIZE
nchecks = int(128 / size)
cairo_surf = cairo.ImageSurface(cairo.FORMAT_ARGB32, 128, 128)
cr = cairo.Context(cairo_surf)
render_checks(cr, size, nchecks)
Gdk.cairo_set_source_pixbuf(cr, pixbuf, 0, 0)
cr.paint()
cairo_surf.flush()
return Gdk.pixbuf_get_from_surface(cairo_surf, 0, 0, 128, 128)
def render_brush_preview_pixbuf(brushinfo, max_edge_tiles=4):
"""Renders brush preview images
:param lib.brush.BrushInfo brushinfo: settings to render
:param int max_edge_tiles: Use at most this many tiles along an edge
:returns: Preview image, at 128x128 pixels
:rtype: GdkPixbuf
This generates the preview image (128px icon) used for brushes which
don't have saved ones. These include brushes picked from .ORA files
where the parent_brush_name doesn't correspond to a brush in the
user's MyPaint brushes - they're used as the default, and for the
Auto button in the Brush Icon editor.
Brushstrokes are inherently unpredictable in size, so the allowable
area is grown until the brush fits or until the rendering becomes
too big. `max_edge_tiles` limits this growth.
"""
assert max_edge_tiles >= 1
brushinfo = brushinfo.clone() # avoid capturing a ref
brush = Brush(brushinfo)
surface = lib.tiledsurface.Surface()
N = lib.tiledsurface.N
for size_in_tiles in range(1, max_edge_tiles):
width = N * size_in_tiles
height = N * size_in_tiles
surface.clear()
fg, spiral = _brush_preview_bg_fg(surface, size_in_tiles, brushinfo)
brushinfo.set_color_rgb(fg)
brush.reset()
# Curve
shape = _variable_pressure_scribble(width, height, size_in_tiles)
surface.begin_atomic()
for dt, x, y, p, xt, yt in shape:
brush.stroke_to(surface.backend, x, y, p, xt, yt, dt)
surface.end_atomic()
# Check rendered size
tposs = surface.tiledict.keys()
outside = min({tx for tx, ty in tposs}) < 0
outside = outside or (min({ty for tx, ty in tposs}) < 0)
outside = outside or (max({tx for tx, ty in tposs}) >= size_in_tiles)
outside = outside or (max({ty for tx, ty in tposs}) >= size_in_tiles)
if not outside:
break
# Convert to pixbuf at the right scale
rect = (0, 0, width, height)
pixbuf = render_as_pixbuf(surface, *rect, alpha=True)
if max(width, height) != 128:
interp = (GdkPixbuf.InterpType.NEAREST if max(width, height) < 128
else GdkPixbuf.InterpType.BILINEAR)
pixbuf = pixbuf.scale_simple(128, 128, interp)
# Composite over a checquered bg via Cairo: shows erases
size = gui.style.ALPHA_CHECK_SIZE
nchecks = int(128 / size)
cairo_surf = cairo.ImageSurface(cairo.FORMAT_ARGB32, 128, 128)
cr = cairo.Context(cairo_surf)
render_checks(cr, size, nchecks)
Gdk.cairo_set_source_pixbuf(cr, pixbuf, 0, 0)
cr.paint()
cairo_surf.flush()
return Gdk.pixbuf_get_from_surface(cairo_surf, 0, 0, 128, 128)