38 lines
1.1 KiB
Text
38 lines
1.1 KiB
Text
let read_ppm ~filename =
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let ic = open_in filename in
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let line = input_line ic in
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if line <> "P6" then invalid_arg "not a P6 ppm file";
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let line = input_line ic in
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let line =
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try if line.[0] = '#' (* skip comments *)
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then input_line ic
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else line
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with _ -> line
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in
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let width, height =
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Scanf.sscanf line "%d %d" (fun w h -> (w, h))
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in
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let line = input_line ic in
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if line <> "255" then invalid_arg "not a 8 bit depth image";
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let all_channels =
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let kind = Bigarray.int8_unsigned
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and layout = Bigarray.c_layout
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in
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Bigarray.Array3.create kind layout 3 width height
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in
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let r_channel = Bigarray.Array3.slice_left_2 all_channels 0
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and g_channel = Bigarray.Array3.slice_left_2 all_channels 1
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and b_channel = Bigarray.Array3.slice_left_2 all_channels 2
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in
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for y = 0 to pred height do
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for x = 0 to pred width do
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r_channel.{x,y} <- (input_byte ic);
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g_channel.{x,y} <- (input_byte ic);
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b_channel.{x,y} <- (input_byte ic);
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done;
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done;
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close_in ic;
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(all_channels,
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r_channel,
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g_channel,
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b_channel)
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