PdfConfiguration class

The parameters pageSize, pageFit, dpi and resamplingMethod interact in a complex way when adding bitmap images (JPEG, PNG, or raw) to the PDF. There are three cases to consider:

  1. pageSize is CUSTOM: in this case dpi is used as the conversion ratio to calculate both the physical page and image sizes in inches from the bitmap dimensions. resamplingMethod is ignored.
  2. pageSize is not CUSTOM AND pageFit is NONE: in this case dpi is used as the conversion ratio to calculate only the physical image size in inches from the bitmap dimensions. The image is centered onto the page. resamplingMethod is ignored.
  3. pageSize is not CUSTOM AND pageFit is not NONE: in this case the page has a pre-determined physical size and we want to stretch the image to fit the page in one of the ways described by pageFit. The image DPI is automatically calculated for each image from the given physical page size, page fit setting and image dimensions. There are two sub-cases to consider: a. resamplingMethod is NONE OR the calculated DPI is less than or equal to dpi: in this case the image is added to the PDF without resampling, which means that the image rectangle is simply rescaled to fit into the page as specified by pageFit and pageSize. b. resamplingMethod is not NONE AND the calculated DPI is greater than dpi: in this case the bitmap of the image is resampled to match dpi using the selected method before adding it to the PDF. This will result in a bitmap that is smaller than the original image and hence, the resulting PDF will be smaller in size.

Constructors

PdfConfiguration.new({PdfAttributes? attributes, PageSize pageSize = PageSize.A4, PageDirection pageDirection = PageDirection.PORTRAIT, PageFit pageFit = PageFit.FIT_IN, int dpi = 72, int jpegQuality = 80, ResamplingMethod resamplingMethod = ResamplingMethod.NONE})
PdfConfiguration.fromJson(Map<String, dynamic> json)
factory

Properties

attributes ↔ PdfAttributes
Attributes.
getter/setter pair
dpi ↔ int
The dpi parameter has two different meanings depending on the value of pageSize and pageFit. If pageSize is CUSTOM or pageFit is NONE, then dpi is the conversion ratio used to convert from units of pixels to physical inches when adding bitmap images (JPEG, PNG, or raw) to the PDF. Otherwise, if resamplingMethod is not NONE, then the image is downscaled if necessary (if the image after being fit to the page has a higher calculated DPI than dpi) to match dpi before adding it to the PDF. Otherwise, the setting is ignored and the calculated image DPI is used instead.
getter/setter pair
hashCode → int
The hash code for this object.
no setterinherited
jpegQuality ↔ int
JPEG quality for images. Applies if an image is added as a cv::Mat and therefore needs to be encoded. Also applies if resamplingMethod not NONE and the image being added needs to be downscaled. Otherwise, when adding JPEG files to the PDF, the files are copied directly into the PDF and not re-encoded, which is many times faster and also preserves the quality of the original.
getter/setter pair
pageDirection ↔ PageDirection
Page direction.
getter/setter pair
pageFit ↔ PageFit
How to fit the image into the page. Only used if pageSize is not CUSTOM. The image can either be stretched to fill the page, in one of three ways, or centered on the page without stretching.
getter/setter pair
pageSize ↔ PageSize
Physical size of the page. If CUSTOM, the page size will be set as the image size at given dpi.
getter/setter pair
resamplingMethod ↔ ResamplingMethod
Resampling method.
getter/setter pair
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited

Methods

noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
toJson({ToJsonConfiguration? config}) → Map<String, dynamic>
toString() → String
A string representation of this object.
inherited

Operators

operator ==(Object other) → bool
The equality operator.
inherited