pdfrum_render/
error.rs

1//! What can go wrong badly enough to abandon a render.
2//!
3//! Almost nothing does. Rendering a damaged page is the normal case, and
4//! every recovery — an undrawable matrix, a shading whose function will not
5//! evaluate, a pattern whose steps are degenerate — is a skipped object and a
6//! [`Diagnostic`](pdfrum_common::Diagnostic), not an error. `Err` is reserved
7//! for "there is no output at all".
8
9/// A render that could not produce a pixmap.
10#[derive(Debug, thiserror::Error, PartialEq, Eq, Clone)]
11#[non_exhaustive]
12pub enum Error {
13    /// The requested target exceeds what a backend can allocate.
14    ///
15    /// `vello_cpu` sizes every scene, pixmap and mask with `u16`, so 65535 is
16    /// the hard ceiling in either axis; the bound is enforced in the engine so
17    /// both backends agree rather than one of them failing later.
18    #[error("render target {width}x{height} exceeds the {limit}px backend limit")]
19    TargetTooLarge {
20        /// The requested width in pixels.
21        width: u32,
22        /// The requested height in pixels.
23        height: u32,
24        /// The largest dimension a backend accepts.
25        limit: u32,
26    },
27
28    /// The requested target has a zero axis, so there is nothing to render
29    /// into.
30    #[error("render target {width}x{height} is empty")]
31    TargetEmpty {
32        /// The requested width in pixels.
33        width: u32,
34        /// The requested height in pixels.
35        height: u32,
36    },
37    /// The requested region does not lie inside the page's device box.
38    #[error(
39        "render region {width}x{height} at ({x}, {y}) is outside the page's {page_width}x{page_height} device box"
40    )]
41    RegionOutOfBounds {
42        /// The region's left edge.
43        x: u32,
44        /// The region's top edge.
45        y: u32,
46        /// The region's width.
47        width: u32,
48        /// The region's height.
49        height: u32,
50        /// The page's full device width under the render transform.
51        page_width: u32,
52        /// The page's full device height under the render transform.
53        page_height: u32,
54    },
55    /// This renderer cannot draw a part of the page; ask for the whole of it.
56    #[error("this renderer cannot draw a region of the page, only the whole page")]
57    RegionUnsupported,
58    /// [`RenderSession::deadline`](crate::RenderSession::deadline) or
59    /// [`RenderSession::cancel`](crate::RenderSession::cancel) passed:
60    /// before the target was allocated, or during the walk, which stops at
61    /// the next object and reports here rather than handing back a page with
62    /// the rest missing.
63    #[error(transparent)]
64    Limit(pdfrum_common::LimitExceeded),
65    /// A PNG could not be encoded — only with the `png` feature. The
66    /// encoder's own message, since its error type is neither comparable nor
67    /// cloneable and this one is both.
68    #[cfg(feature = "png")]
69    #[error("PNG encoding failed: {0}")]
70    Png(String),
71    /// A file could not be written — only with the `png` feature; the I/O
72    /// error's message.
73    #[cfg(feature = "png")]
74    #[error("writing the file failed: {0}")]
75    Io(String),
76}
77
78#[cfg(feature = "png")]
79impl From<png::EncodingError> for Error {
80    fn from(error: png::EncodingError) -> Self {
81        Error::Png(error.to_string())
82    }
83}
84
85#[cfg(feature = "png")]
86impl From<std::io::Error> for Error {
87    fn from(error: std::io::Error) -> Self {
88        Error::Io(error.to_string())
89    }
90}
pdfrum_render/error.rs

pdfrum_render/
error.rs
