jaculabilis/danbooru
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

media assets: fix dimensions of flash files.

Browse Source 
Use ExifTool to get the dimensions of Flash files instead of calculating
it ourselves. Avoids copying third-party code.

Fixes a bug where Flash files with fractional dimensions (e.g. 607.6 x 756.6)
had their dimensions rounded down instead of rounded up.

Fixes another bug where Flash files could return negative dimensions.
This happened for two files:

* https://danbooru.donmai.us/media_assets/228662 (-179.2 x -339.2)
* https://danbooru.donmai.us/media_assets/228664 (-179.2 x -339.2)

Now we round these up to 1x1. This is still wrong, but it's less wrong than before.
This commit is contained in:
evazion
2022-10-31 17:12:52 -05:00
parent 2f2c73eebb
commit acc511ab7d
3 changed files with 9 additions and 88 deletions
Download Patch File Download Diff File Expand all files Collapse all files

88
app/logical/media_file/flash.rb
View File

@@ -1,91 +1,9 @@
# frozen_string_literal: true
# This file contains code derived from
# https://github.com/dim/ruby-imagespec/blob/f2f3ce8bb5b1b411f8658e66a891a095261d94c0/lib/image_spec/parser/swf.rb
#
# Copyright (c) 2020, Danbooru Project contributors
# Copyright (c) 2008, Brandon Anderson (anderson.brandon@gmail.com)
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without modification,
# are permitted provided that the following conditions are met:
#
# Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# Neither the name of the original author nor the names of contributors
# may be used to endorse or promote products derived from this software
# without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
class MediaFile::Flash < MediaFile
# XXX Some Flash files have fractional dimensions; round up to nearest integer.
# XXX Some Flash files have negative dimensions; clamp to positive numbers.
def dimensions
# Read the entire stream into memory because the
# dimensions aren't stored in a standard location
contents = File.read(file.path, binmode: true).force_encoding("ASCII-8BIT")
# Our 'signature' is the first 3 bytes
# Either FWS or CWS. CWS indicates compression
signature = contents[0..2]
# SWF version
_version = contents[3].unpack('C').join.to_i
# Determine the length of the uncompressed stream
length = contents[4..7].unpack('V').join.to_i
# If we do, in fact, have compression
if signature == 'CWS'
# Decompress the body of the SWF
body = Zlib::Inflate.inflate(contents[8..length])
# And reconstruct the stream contents to the first 8 bytes (header)
# Plus our decompressed body
contents = contents[0..7] + body
end
# Determine the nbits of our dimensions rectangle
nbits = contents.unpack('C' * contents.length)[8] >> 3
# Determine how many bits long this entire RECT structure is
rectbits = 5 + nbits * 4 # 5 bits for nbits, as well as nbits * number of fields (4)
# Determine how many bytes rectbits composes (ceil(rectbits/8))
rectbytes = (rectbits.to_f / 8).ceil
# Unpack the RECT structure from the stream in little-endian bit order, then join it into a string
rect = contents[8..(8 + rectbytes)].unpack("#{'B8' * rectbytes}").join
# Read in nbits incremenets starting from 5
dimensions = []
4.times do |n|
s = 5 + (n * nbits) # Calculate our start index
e = s + (nbits - 1) # Calculate our end index
dimensions[n] = rect[s..e].to_i(2) # Read that range (binary) and convert it to an integer
end
# The values we have here are in "twips"
# 20 twips to a pixel (that's why SWFs are fuzzy sometimes!)
width = (dimensions[1] - dimensions[0]) / 20
height = (dimensions[3] - dimensions[2]) / 20
[width, height]
[metadata.width.ceil.clamp(1..), metadata.height.ceil.clamp(1..)]
end
memoize :dimensions
end

3
script/fixes/123_refresh_media_metadata.rb
View File

@@ -2,6 +2,7 @@
require_relative "base"
CurrentUser.user = User.system
condition = ENV.fetch("COND", "TRUE")
fix = ENV.fetch("FIX", "false").truthy?
@@ -17,6 +18,7 @@ MediaAsset.active.where(condition).find_each do |asset|
# Setting `file` updates the metadata if it's different.
asset.file = media_file
asset.media_metadata.file = media_file
asset.post.assign_attributes(image_width: asset.image_width, image_height: asset.image_height, file_ext: asset.file_ext, file_size: asset.file_size) if asset.post.present?
old = asset.media_metadata.metadata_was.to_h
new = asset.media_metadata.metadata.to_h
@@ -24,6 +26,7 @@ MediaAsset.active.where(condition).find_each do |asset|
puts ({ id: asset.id, **asset.changes, **metadata_changes }).to_json
if fix
asset.post.save! if asset.post&.changed?
asset.save! if asset.changed?
asset.media_metadata.save! if asset.media_metadata.changed?
end

6
test/unit/media_file_test.rb
View File

@@ -46,7 +46,7 @@ class MediaFileTest < ActiveSupport::TestCase
end
should "determine the correct dimensions for a flash file" do
assert_equal([607, 756], MediaFile.open("test/files/compressed.swf").dimensions)
assert_equal([608, 757], MediaFile.open("test/files/compressed.swf").dimensions)
end
should "work if called twice" do
@@ -55,8 +55,8 @@ class MediaFileTest < ActiveSupport::TestCase
assert_equal([500, 335], mf.dimensions)
mf = MediaFile.open("test/files/compressed.swf")
assert_equal([607, 756], mf.dimensions)
assert_equal([607, 756], mf.dimensions)
assert_equal([608, 757], mf.dimensions)
assert_equal([608, 757], mf.dimensions)
end
should "work for a video if called twice" do