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//! Defines the [PdfBitmap] struct, a lazily-generated bitmap rendering of a single
//! `PdfPage`.
use crate::bindgen::{
FPDFBitmap_BGR, FPDFBitmap_BGRA, FPDFBitmap_BGRx, FPDFBitmap_Gray, FPDFBitmap_Unknown,
FPDF_BITMAP,
};
use crate::bindings::PdfiumLibraryBindings;
use crate::bitmap_config::PdfBitmapRenderSettings;
use crate::color::PdfColor;
use crate::error::PdfiumError;
use image::{DynamicImage, ImageBuffer};
#[cfg(target_arch = "wasm32")]
use wasm_bindgen::{Clamped, JsValue};
use crate::page::PdfPage;
#[cfg(target_arch = "wasm32")]
use web_sys::ImageData;
/// The pixel format of the rendered image data in the backing buffer of a [PdfBitmap].
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum PdfBitmapFormat {
Gray = FPDFBitmap_Gray as isize,
BGR = FPDFBitmap_BGR as isize,
BRGx = FPDFBitmap_BGRx as isize,
BGRA = FPDFBitmap_BGRA as isize,
}
impl PdfBitmapFormat {
#[inline]
#[allow(non_upper_case_globals)]
pub(crate) fn from_pdfium(format: u32) -> Result<Self, PdfiumError> {
match format {
FPDFBitmap_Unknown => Err(PdfiumError::UnknownBitmapFormat),
FPDFBitmap_Gray => Ok(PdfBitmapFormat::Gray),
FPDFBitmap_BGR => Ok(PdfBitmapFormat::BGR),
FPDFBitmap_BGRx => Ok(PdfBitmapFormat::BRGx),
FPDFBitmap_BGRA => Ok(PdfBitmapFormat::BGRA),
_ => Err(PdfiumError::UnknownBitmapFormat),
}
}
#[inline]
pub(crate) fn as_pdfium(&self) -> u32 {
match self {
PdfBitmapFormat::Gray => FPDFBitmap_Gray,
PdfBitmapFormat::BGR => FPDFBitmap_BGR,
PdfBitmapFormat::BRGx => FPDFBitmap_BGRx,
PdfBitmapFormat::BGRA => FPDFBitmap_BGRA,
}
}
}
/// A rotation transformation that should be applied to a [PdfPage] when it is rendered
/// into a [PdfBitmap].
#[derive(Copy, Clone, Debug, PartialEq)]
pub enum PdfBitmapRotation {
None,
Degrees90,
Degrees180,
Degrees270,
}
impl PdfBitmapRotation {
#[inline]
pub(crate) fn from_pdfium(rotate: i32) -> Result<Self, PdfiumError> {
match rotate {
0 => Ok(PdfBitmapRotation::None),
1 => Ok(PdfBitmapRotation::Degrees90),
2 => Ok(PdfBitmapRotation::Degrees180),
3 => Ok(PdfBitmapRotation::Degrees270),
_ => Err(PdfiumError::UnknownBitmapRotation),
}
}
#[inline]
pub(crate) fn as_pdfium(&self) -> i32 {
match self {
PdfBitmapRotation::None => 0,
PdfBitmapRotation::Degrees90 => 1,
PdfBitmapRotation::Degrees180 => 2,
PdfBitmapRotation::Degrees270 => 3,
}
}
}
/// A rendered image of a single [PdfPage] at a specific width and height.
///
/// By default, [PdfBitmap] is lazy; it will not render its page into a bitmap until
/// it is required to do so in order to return a byte buffer or an `Image::DynamicImage`.
/// If preferred, rendering can be initiated manually by calling the [PdfBitmap::render()] function.
/// Once rendered, the page will not be re-rendered.
pub struct PdfBitmap<'a> {
bitmap_handle: FPDF_BITMAP,
config: PdfBitmapRenderSettings,
is_rendered: bool,
page: &'a PdfPage<'a>,
bindings: &'a dyn PdfiumLibraryBindings,
}
impl<'a> PdfBitmap<'a> {
pub(crate) fn from_pdfium(
bitmap_handle: FPDF_BITMAP,
config: PdfBitmapRenderSettings,
page: &'a PdfPage<'a>,
bindings: &'a dyn PdfiumLibraryBindings,
) -> Self {
PdfBitmap {
config,
bitmap_handle,
is_rendered: false,
page,
bindings,
}
}
/// Returns the width of the image in this [PdfBitmap], in pixels.
#[inline]
pub fn width(&self) -> u32 {
self.config.width as u32
}
/// Returns the height of the image in this [PdfBitmap], in pixels.
#[inline]
pub fn height(&self) -> u32 {
self.config.height as u32
}
/// Returns the pixel format of the image in this [PdfBitmap].
#[inline]
pub fn format(&self) -> PdfBitmapFormat {
PdfBitmapFormat::from_pdfium(self.config.format as u32).unwrap()
}
/// Returns the rotation setting that will be applied to this page during rendering.
#[inline]
pub fn rotation(&self) -> PdfBitmapRotation {
PdfBitmapRotation::from_pdfium(self.config.rotate).unwrap()
}
/// Returns a new `Image::DynamicImage` created from the bitmap buffer backing
/// this [PdfBitmap], rendering the referenced page if necessary.
pub fn as_image(&mut self) -> DynamicImage {
ImageBuffer::from_raw(
self.config.width as u32,
self.config.height as u32,
self.as_bytes().to_owned(),
)
.map(DynamicImage::ImageRgba8)
.unwrap()
}
/// Returns an immutable reference to the bitmap buffer backing this [PdfBitmap],
/// rendering the referenced page if necessary.
pub fn as_bytes(&mut self) -> &'a [u8] {
self.render();
let buffer_length = self.bindings.FPDFBitmap_GetStride(self.bitmap_handle)
* self.bindings.FPDFBitmap_GetHeight(self.bitmap_handle);
let buffer_start = self.bindings.FPDFBitmap_GetBuffer(self.bitmap_handle);
unsafe { std::slice::from_raw_parts(buffer_start as *const u8, buffer_length as usize) }
}
/// Returns a new Javascript `ImageData` object created from the bitmap buffer backing
/// this [PdfBitmap], rendering the referenced page if necessary. The resulting ImageData
/// can be easily displayed in an HTML <canvas> element like so:
///
/// `canvas.getContext('2d').putImageData(image_data);`
///
/// This function is only available when compiling to WASM.
#[cfg(target_arch = "wasm32")]
pub fn as_image_data(&mut self) -> Result<ImageData, JsValue> {
ImageData::new_with_u8_clamped_array_and_sh(
Clamped(self.as_bytes()),
self.width(),
self.height(),
)
}
/// Renders this page into a bitmap buffer. Once rendered, the page will not be
/// re-rendered.
///
/// It is generally unnecessary to call this function directly, since PdfBitmap
/// will automatically initiate rendering itself on the first call to either
/// the [PdfBitmap::as_bytes()] function or the [PdfBitmap::as_image()] function.
pub fn render(&mut self) {
if self.is_rendered {
// The page has already been rendered.
return;
}
// Clear the bitmap buffer by setting every pixel to white.
self.bindings.FPDFBitmap_FillRect(
self.bitmap_handle,
0,
0,
self.config.width,
self.config.height,
PdfColor::SOLID_WHITE.as_pdfium_color(),
);
// Render the PDF page into the bitmap buffer.
self.bindings.FPDF_RenderPageBitmap(
self.bitmap_handle,
*self.page.get_handle(),
0,
0,
self.config.width,
self.config.height,
self.config.rotate,
self.config.render_flags,
);
if let Some(form) = self.page.get_document().form() {
if self.config.do_render_form_data {
// Render user-supplied form data, if any, as an overlay on top of the page.
for (form_field_type, (color, alpha)) in self.config.form_field_highlight.iter() {
self.bindings.FPDF_SetFormFieldHighlightColor(
*form.get_handle(),
*form_field_type,
*color,
);
self.bindings
.FPDF_SetFormFieldHighlightAlpha(*form.get_handle(), *alpha);
}
self.bindings.FPDF_FFLDraw(
*form.get_handle(),
self.bitmap_handle,
*self.page.get_handle(),
0,
0,
self.config.width,
self.config.height,
self.config.rotate,
self.config.render_flags,
);
}
}
self.is_rendered = true;
}
}
impl<'a> Drop for PdfBitmap<'a> {
/// Closes this [PdfBitmap], releasing the memory held by the bitmap buffer.
#[inline]
fn drop(&mut self) {
self.bindings.FPDFBitmap_Destroy(self.bitmap_handle);
}
}