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//! Pikchr image creation binding //! //! This crate provides a binding for the //! [`pikchr`](https://pikchr.org/home/doc/trunk/homepage.md) diagramming //! language. Using this crate you can convert PIC-like markup //! into SVG diagrams trivially. If you are embedding into HTML then //! you can have any errors generated as HTML, otherwise errors are //! generated as plain text. //! //! The main interface is the [`Pikchr`] struct, specifically its //! [`Pikchr::render`] function. //! //! ``` //! use pikchr::{Pikchr, PikchrFlags}; //! //! let INPUT = r#" //! arrow right 200% "Markdown" "Source" //! box rad 10px "Markdown" "Formatter" "(docs.rs/markdown)" fit //! arrow right 200% "HTML+SVG" "Output" //! arrow <-> down 70% from last box.s //! box same "Pikchr" "Formatter" "(docs.rs/pikchr)" fit //! "#; //! //! let pic = Pikchr::render(INPUT, None, PikchrFlags::default()).unwrap(); //! //! println!("{}", pic); //! ``` //! <svg xmlns='http://www.w3.org/2000/svg' viewBox="0 0 475.315 195.84"><polygon points="146,37 134,41 134,33" style="fill:rgb(0,0,0)"/><path d="M2,37L140,37" style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" /><text x="74" y="25" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Markdown</text><text x="74" y="49" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Source</text><path d="M161,72L309,72A15 15 0 0 0 324 57L324,17A15 15 0 0 0 309 2L161,2A15 15 0 0 0 146 17L146,57A15 15 0 0 0 161 72Z" style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" /><text x="235" y="17" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Markdown</text><text x="235" y="37" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Formatter</text><text x="235" y="57" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">(docs.rs/markdown)</text><polygon points="468,37 457,41 457,33" style="fill:rgb(0,0,0)"/><path d="M324,37L463,37" style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" /><text x="396" y="25" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">HTML+SVG</text><text x="396" y="49" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Output</text><polygon points="235,72 239,84 231,84" style="fill:rgb(0,0,0)"/><polygon points="235,123 231,111 239,111" style="fill:rgb(0,0,0)"/><path d="M235,78L235,117" style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" /><path d="M178,193L292,193A15 15 0 0 0 307 178L307,138A15 15 0 0 0 292 123L178,123A15 15 0 0 0 163 138L163,178A15 15 0 0 0 178 193Z" style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" /><text x="235" y="138" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Pikchr</text><text x="235" y="158" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Formatter</text><text x="235" y="178" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">(docs.rs/pikchr)</text></svg> use libc::{c_char, c_int, c_uint, c_void, free}; use std::ffi::{CStr, CString}; use std::fmt; use std::ops::Deref; pub mod raw { use libc::{c_char, c_int, c_uint}; extern "C" { /// The main interface. Invoke this routine to translate PIKCHR source /// text into SVG. The SVG is returned in a buffer obtained from malloc(). /// The caller is responsible for freeing the buffer. /// /// If an error occurs, *pnWidth is filled with a negative number and /// the return buffer contains error message text instead of SVG. By /// default, the error message is HTML encoded. However, error messages /// come out as plaintext if the PIKCHR_PLAINTEXT_ERRORS flag is included /// as one of the bits in the mFlags parameter. /// /// - `zText`: Input PIKCHR source text. zero-terminated /// - `zClass`: Add class="%s" to <svg> markup /// - `mFlags`: Flags used to influence rendering behavior /// - `pnWidth`: OUT: Write width of <svg> here, if not NULL /// - `pnHeight`: OUT: Write height here, if not NULL #[allow(non_snake_case)] pub fn pikchr( zText: *const c_char, zClass: *const c_char, mFlags: c_uint, pnWidth: *mut c_int, pnHeight: *mut c_int, ) -> *mut c_char; } /// Include PIKCHR_PLAINTEXT_ERRORS among the bits of mFlags on the 3rd /// argument to pikchr() in order to cause error message text to come out /// as text/plain instead of as text/html pub const PIKCHR_PLAINTEXT_ERRORS: c_uint = 0x0001; } /// Flags for converting pikchr source /// /// You can construct a default set of flags using the [`std::default::Default`] trait /// /// The default flags will generate plain text errors #[derive(Copy, Clone)] pub struct PikchrFlags { plain_errors: bool, } impl PikchrFlags { /// Return whether or not plain text errors will be generated /// /// ``` /// # use pikchr::PikchrFlags; /// let flags = PikchrFlags::default(); /// assert!(flags.plain_errors()) /// ``` pub fn plain_errors(&self) -> bool { self.plain_errors } /// Request plain text errors be generated /// /// ``` /// # use pikchr::PikchrFlags; /// let mut flags = PikchrFlags::default(); /// flags.generate_plain_errors(); /// assert!(flags.plain_errors()); /// ``` pub fn generate_plain_errors(&mut self) -> &mut PikchrFlags { self.plain_errors = true; self } /// Request help encoded errors be generated /// /// ``` /// # use pikchr::PikchrFlags; /// let mut flags = PikchrFlags::default(); /// flags.generate_html_errors(); /// assert!(!flags.plain_errors()); /// ``` pub fn generate_html_errors(&mut self) -> &mut PikchrFlags { self.plain_errors = false; self } } impl Into<c_uint> for PikchrFlags { fn into(self) -> c_uint { if self.plain_errors { raw::PIKCHR_PLAINTEXT_ERRORS } else { 0 } } } impl std::default::Default for PikchrFlags { fn default() -> Self { Self { plain_errors: true } } } /// A rendered pikchr diagram /// /// Pikchr renders diagrams as SVG. This SVG is a given width /// and height. The Pikchr derefs to the SVG string, or you /// can access it explicitly. The width and height are accessible /// as plain numbers. pub struct Pikchr { rendered: *const c_char, width: c_int, height: c_int, } impl Drop for Pikchr { fn drop(&mut self) { if self.rendered.is_null() { unsafe { free(self.rendered as *mut c_void); } self.rendered = std::ptr::null(); } } } impl Deref for Pikchr { type Target = str; fn deref(&self) -> &Self::Target { // We're assuming a Pikchr instance can only // be constructed from valid utf8 and thus can // only contain valid utf8 unsafe { let cstr = CStr::from_ptr(self.rendered); std::str::from_utf8_unchecked(cstr.to_bytes()) } } } impl fmt::Display for Pikchr { fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result { fmt.write_str(self) } } impl Pikchr { /// Render some input pikchr source as an SVG /// /// You can convert arbitrary pikchr source into an SVG using this function. /// The class name is optional, and the flags field controls the generation /// of errors. Since pikchr does not have a structured error format, the /// returned error is simply a string. /// /// ``` /// # use pikchr::{Pikchr, PikchrFlags}; /// let image = Pikchr::render(r#" /// arrow right 200% "Markdown" "Source" /// box rad 10px "Markdown" "Formatter" "(markdown.c)" fit /// arrow right 200% "HTML+SVG" "Output" /// arrow <-> down 70% from last box.s /// box same "Pikchr" "Formatter" "(pikchr.c)" fit"#, /// None, PikchrFlags::default()) /// .unwrap(); /// assert!(image.contains("<svg")) /// ``` pub fn render(source: &str, class: Option<&str>, flags: PikchrFlags) -> Result<Pikchr, String> { let mut width: c_int = 0; let mut height: c_int = 0; let source = CString::new(source).map_err(|e| format!("{:?}", e))?; let res: *mut c_char = unsafe { raw::pikchr( source.as_ptr() as *const c_char, class .map(|s| s.as_ptr() as *const c_char) .unwrap_or(std::ptr::null()), flags.into(), &mut width as *mut c_int, &mut height as *mut c_int, ) }; if width < 0 { let err = unsafe { CStr::from_ptr(res) }; let err = err.to_bytes(); let err = String::from_utf8_lossy(err).into_owned(); unsafe { free(res as *mut c_void); } Err(err) } else { Ok(Pikchr { rendered: res, width, height, }) } } /// Retrieve the width of this Pikchr /// /// ``` /// # use pikchr::{Pikchr, PikchrFlags}; /// # let pic = Pikchr::render(r#"arrow right 200% "Markdown" "Source""#, /// # None, PikchrFlags::default()).unwrap(); /// println!("Picture is {} pixels wide", pic.width()); /// ``` pub fn width(&self) -> isize { self.width as isize } /// Retrieve the height of this Pikchr /// /// ``` /// # use pikchr::{Pikchr, PikchrFlags}; /// # let pic = Pikchr::render(r#"arrow right 200% "Markdown" "Source""#, /// # None, PikchrFlags::default()).unwrap(); /// println!("Picture is {} pixels tall", pic.height()); /// ``` pub fn height(&self) -> isize { self.height as isize } /// Retrieve the rendered pikchr (same as dereferencing) /// /// ``` /// # use pikchr::{Pikchr, PikchrFlags}; /// # let pic = Pikchr::render(r#"arrow right 200% "Makdown" "Source""#, /// # None, PikchrFlags::default()).unwrap(); /// println!("Picture content:\n{}", pic.rendered()); /// ``` pub fn rendered(&self) -> &str { &*self } } #[cfg(test)] mod tests { use super::*; #[test] fn validate_diagram() { const SOURCE: &str = r#"arrow right 200% "Markdown" "Source""#; const OUTPUT: &str = r#"<svg xmlns='http://www.w3.org/2000/svg' viewBox="0 0 152.64 47.88"> <polygon points="146,23 134,28 134,19" style="fill:rgb(0,0,0)"/> <path d="M2,23L140,23" style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" /> <text x="74" y="12" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Markdown</text> <text x="74" y="35" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Source</text> </svg> "#; let flags = PikchrFlags::default(); let p = Pikchr::render(SOURCE, None, flags).unwrap(); assert_eq!(OUTPUT, p.rendered()); } }