Controlling Image Conversion
Titania Delivery uses a tool called ImageMagick to perform most graphic conversion. For source formats handled by ImageMatick, you can control the conversion using the following special metadata names.
_td.imageConversion.args.vector-
Controls the conversion of EPS graphics.
_td.imageConversion.args.raster- Controls the conversion of TIFF graphics.
_td.imageConversion.args- If neither the
vectororrastermetadata is set, you can use this as shorthand for image conversion of all graphic types, but this entry will be ignored if the suitable more-specific name is also specified.
These settings can be set at either the project or file level. If set at both the
project and
the file level, the file-level metadata will take precedence. Any
_td.imageConversion.args entry on a file will take precedence over any
more-specific setting from the project level.
Default Value for EPS Graphics
The default value for the _td.imageConversion.args.vector option is as
follows.
-quality 75 -density 288 -resize 25%
-quality 75- Sets the quality to 75%. Modifying the output quality affects the final compression level as well as the image quality.
-density 288- Sets the pixel density to to 288 pixels/inch. This is four times the default screen resolution of 72 pixels/inch.
-resize 25%- Scales the graphic by 25%, thus effectively "undoing" the higher-than-normal pixel density. This has the effect of reducing hard pixels in rounded curves via anti-aliasing.
The output graphic will be scaled to the same size as any raster preview embedded
in the EPS
graphic. In some cases, this can be quite small, and the ultimate dimensions may need
to be
explicitly specified via the -resize option.
Default Value for TIFF Graphics
The default value for the _td.imageConversion.args.raster option is as
follows.
-quality 75 -define tiff:exif-properties=false
-quality 75- Sets the quality to 75%. Modifying the output quality affects the final compression level as well as the image quality.
-define tiff:exif-properties=false- Causes ImageMagick to skip reading EXIF properties in the graphic. Otherwise, if a graphic does not contain EXIF properties, or contains invalid/unexpected entries, the conversion will fail.