magick_rust 2.1.0

/*
 * Copyright 2015-2017 Nathan Fiedler
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
//!
//! "Safe" wrapper around the low-level bindings to ImageMagick.
//!
//! Prior to using the ImageMagick system, the application should invoke
//! `magick_wand_genesis()`, which maps directly to `MagickWandGenesis`.
//! Likewise, when an application is done using ImageMagick, invoke the
//! `magick_wand_terminus()` function, which maps to `MagickWandTerminus`.
//!

// Make the Rust bindings compile cleanly, despite being very un-Rust-like
// wrappers around C code.
#![allow(dead_code)]
#![allow(non_upper_case_globals)]
#![allow(non_camel_case_types)]
#![allow(non_snake_case)]

use libc::size_t;
use std::ffi::{CStr, CString};
use std::slice::from_raw_parts;

pub use crate::result::MagickError;
use crate::result::Result;
pub use crate::types::*;
pub use crate::wand::*;

mod conversions;
mod result;
mod types;
mod wand;
include!(concat!(env!("OUT_DIR"), "/bindings.rs"));

/// This function must be called before any other ImageMagick operations
/// are attempted. This function is safe to be called repeatedly.
pub fn magick_wand_genesis() {
    unsafe {
        if bindings::IsMagickWandInstantiated() == bindings::MagickBooleanType::MagickFalse {
            bindings::MagickWandGenesis()
        }
    }
}

/// This function should be called when ImageMagick is no longer needed.
/// This function is safe to be called repeatedly.
///
/// # Warning
///
/// All `MagickWand`, `DrawingWand`, and `PixelWand` values must be dropped
/// **before** calling this function. Each wand's `Drop` impl calls
/// `Destroy<Wand>` on the underlying pointer, and invoking those after
/// `MagickWandTerminus` has torn down the global ImageMagick environment
/// is undefined behavior (typically a crash on process exit). If a wand is
/// still in scope, end the scope first or call `drop(wand)` explicitly
/// before calling this function.
pub fn magick_wand_terminus() {
    unsafe {
        if bindings::IsMagickWandInstantiated() == bindings::MagickBooleanType::MagickTrue {
            bindings::MagickWandTerminus();
        }
    }
}

pub fn magick_query_fonts(pattern: &str) -> Result<Vec<String>> {
    let mut number_fonts: size_t = 0;
    let c_string = CString::new(pattern).map_err(|_| "could not convert to cstring")?;
    let ptr =
        unsafe { bindings::MagickQueryFonts(c_string.as_ptr(), &mut number_fonts as *mut size_t) };
    if ptr.is_null() {
        Err(MagickError(
            "null ptr returned by magick_query_fonts".to_string(),
        ))
    } else {
        let mut v = Vec::new();
        let c_str_ptr_slice = unsafe { from_raw_parts(ptr, number_fonts as usize) };
        for c_str_ptr in c_str_ptr_slice {
            let c_str = unsafe { CStr::from_ptr(*c_str_ptr) };
            v.push(c_str.to_string_lossy().into_owned())
        }
        Ok(v)
    }
}