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ImageWidget: Always return a bb, even on decoding failure.

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(In which case we return a checkerboard pattern).

ScreenSaver: Make sure the choose image/folder/document settings
report what the code actually does on empty settings...
This commit is contained in:
NiLuJe
2022-06-12 20:24:52 +02:00
parent a4f6693919
commit 6ea292ef13
3 changed files with 49 additions and 3 deletions
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31
frontend/ui/renderimage.lua
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@@ -303,4 +303,35 @@ function RenderImage:renderSVGImageFileWithMupdf(filename, width, height, zoom)
return bb -- pre-multiplied alpha: no is_straight_alpha=true
end
--- Renders a checkerboard pattern (useful as a fallback after a decoding failure)
function RenderImage:renderCheckerboard(width, height, bb_type)
width = width or 800
height = height or 800
local bb = Blitbuffer.new(width, height, bb_type or Blitbuffer.TYPE_BB8)
local checker_size = bit.rshift(math.min(width, height), 4)
local pen_color = Blitbuffer.COLOR_BLACK
local row_start
for y = 0, height - 1, checker_size do
row_start = pen_color
for x = 0, width - 1, checker_size do
-- BBs are zero-initialized (i.e., black)
if pen_color == Blitbuffer.COLOR_WHITE then
bb:paintRect(x, y, checker_size, checker_size, Blitbuffer.COLOR_WHITE)
-- Alternate pen color every "column"
pen_color = Blitbuffer.COLOR_BLACK
else
pen_color = Blitbuffer.COLOR_WHITE
end
end
-- Alternate initial pen color every "row"
if row_start == Blitbuffer.COLOR_WHITE then
pen_color = Blitbuffer.COLOR_BLACK
else
pen_color = Blitbuffer.COLOR_WHITE
end
end
return bb
end
return RenderImage