2ffe973275
These other formats aren't actually generated during upload, but support for creating them is there. Also tune the parameters for generating JPEGs: * Use Q=85 instead of Q=90 because Q=85 enables 4:2:0 chroma subsampling, while Q=90 doesn't use subsampling. Subsampling reduces filesize by ~30% in most cases. It does reduce quality for certain images, particularly for images with lots of bright red, but in most cases the quality difference isn't noticeable. * Enable several MozJPEG-specific options, including trellis quantization and scan optimization. These reduce filesize without reducing quality, at the cost of slower encoding times.
132 lines
3.9 KiB
Ruby
132 lines
3.9 KiB
Ruby
# A MediaFile for a JPEG, PNG, or GIF file. Uses libvips for resizing images.
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#
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# @see https://github.com/libvips/ruby-vips
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# @see https://libvips.github.io/libvips/API/current
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class MediaFile::Image < MediaFile
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def dimensions
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image.size
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rescue Vips::Error
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[0, 0]
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end
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def is_corrupt?
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image.stats
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false
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rescue Vips::Error
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true
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end
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def duration
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return nil if !is_animated?
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video.duration
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end
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def frame_count
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if file_ext == :gif
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image.get("n-pages")
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elsif file_ext == :png
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metadata.fetch("PNG:AnimationFrames", 1)
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else
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nil
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end
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end
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def frame_rate
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return nil if !is_animated? || frame_count.nil? || duration.nil? || duration == 0
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frame_count / duration
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end
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def channels
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image.bands
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end
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def colorspace
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image.interpretation
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end
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def resize(max_width, max_height, format: :jpeg, **options)
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# @see https://www.libvips.org/API/current/Using-vipsthumbnail.md.html
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# @see https://www.libvips.org/API/current/libvips-resample.html#vips-thumbnail
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if colorspace == :srgb
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, import_profile: "srgb", export_profile: "srgb", **options)
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elsif colorspace == :cmyk
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# Leave CMYK as CMYK for better color accuracy than sRGB.
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, import_profile: "cmyk", export_profile: "cmyk", intent: :relative, **options)
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elsif colorspace == :"b-w" && has_embedded_profile?
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# Convert greyscale to sRGB so that the color profile is properly applied before we strip it.
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, export_profile: "srgb", **options)
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elsif colorspace == :"b-w"
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# Otherwise, leave greyscale without a profile as greyscale because
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# converting it to sRGB would change it from 1 channel to 3 channels.
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resized_image = preview_frame.image.thumbnail_image(max_width, height: max_height, **options)
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else
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raise NotImplementedError
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end
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output_file = Tempfile.new(["image-preview-#{md5}", ".#{format.to_s}"])
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case format.to_sym
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when :jpeg
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# https://www.libvips.org/API/current/VipsForeignSave.html#vips-jpegsave
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resized_image.jpegsave(output_file.path, Q: 85, background: 255, strip: true, interlace: true, optimize_coding: true, optimize_scans: true, trellis_quant: true, overshoot_deringing: true, quant_table: 3)
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when :webp
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# https://www.libvips.org/API/current/VipsForeignSave.html#vips-webpsave
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resized_image.webpsave(output_file.path, Q: 85, preset: :drawing, effort: 4, strip: true)
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when :avif
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# https://www.libvips.org/API/current/VipsForeignSave.html#vips-heifsave
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resized_image.heifsave(output_file.path, Q: 40, compression: :av1, effort: 4, strip: true)
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else
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raise NotImplementedError
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end
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MediaFile::Image.new(output_file)
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end
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def preview(max_width, max_height, **options)
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w, h = MediaFile.scale_dimensions(width, height, max_width, max_height)
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resize(w, h, size: :force, **options)
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end
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def crop(max_width, max_height)
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resize(max_width, max_height, crop: :attention)
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end
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def preview_frame
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if is_animated?
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FFmpeg.new(file).smart_video_preview
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else
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self
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end
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end
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def is_animated?
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frame_count.to_i > 1
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end
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def is_animated_gif?
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file_ext == :gif && is_animated?
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end
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def is_animated_png?
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file_ext == :png && is_animated?
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end
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# Return true if the image has an embedded ICC color profile.
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def has_embedded_profile?
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image.icc_import(embedded: true)
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true
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rescue Vips::Error
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false
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end
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# @return [Vips::Image] the Vips image object for the file
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def image
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Vips::Image.new_from_file(file.path, fail: true).autorot
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end
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def video
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FFmpeg.new(file)
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end
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memoize :image, :video, :dimensions, :is_corrupt?, :is_animated_gif?, :is_animated_png?
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end
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