1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
use std::io;
use std::io::{Write, Seek, BufRead, BufReader, BufWriter};
use std::path::Path;
use std::fs::File;
use std::iter;
use std::ascii::AsciiExt;
use num_iter;

#[cfg(feature = "pnm")]
use pnm;
#[cfg(feature = "ppm")]
use ppm;
#[cfg(feature = "gif_codec")]
use gif;
#[cfg(feature = "webp")]
use webp;
#[cfg(feature = "jpeg")]
use jpeg;
#[cfg(feature = "png_codec")]
use png;
#[cfg(feature = "tiff")]
use tiff;
#[cfg(feature = "tga")]
use tga;
#[cfg(feature = "bmp")]
use bmp;
#[cfg(feature = "ico")]
use ico;
#[cfg(feature = "hdr")]
use hdr;

use color;
use buffer::{ImageBuffer, ConvertBuffer, Pixel, GrayImage, GrayAlphaImage, RgbImage, RgbaImage};
use imageops;
use image;
use image:: {
    GenericImage,
    ImageDecoder,
    ImageResult,
    ImageFormat,
};

use image::DecodingResult::{U8};

/// A Dynamic Image
#[derive(Clone)]
pub enum DynamicImage {
    /// Each pixel in this image is 8-bit Luma
    ImageLuma8(GrayImage),

    /// Each pixel in this image is 8-bit Luma with alpha
    ImageLumaA8(GrayAlphaImage),

    /// Each pixel in this image is 8-bit Rgb
    ImageRgb8(RgbImage),

    /// Each pixel in this image is 8-bit Rgb with alpha
    ImageRgba8(RgbaImage),
}

macro_rules! dynamic_map(
        ($dynimage: expr, ref $image: ident => $action: expr) => (
                match $dynimage {
                        DynamicImage::ImageLuma8(ref $image) => DynamicImage::ImageLuma8($action),
                        DynamicImage::ImageLumaA8(ref $image) => DynamicImage::ImageLumaA8($action),
                        DynamicImage::ImageRgb8(ref $image) => DynamicImage::ImageRgb8($action),
                        DynamicImage::ImageRgba8(ref $image) => DynamicImage::ImageRgba8($action),
                }
        );

        ($dynimage: expr, ref mut $image: ident => $action: expr) => (
                match $dynimage {
                        DynamicImage::ImageLuma8(ref mut $image) => DynamicImage::ImageLuma8($action),
                        DynamicImage::ImageLumaA8(ref mut $image) => DynamicImage::ImageLumaA8($action),
                        DynamicImage::ImageRgb8(ref mut $image) => DynamicImage::ImageRgb8($action),
                        DynamicImage::ImageRgba8(ref mut $image) => DynamicImage::ImageRgba8($action),
                }
        );

        ($dynimage: expr, ref $image: ident -> $action: expr) => (
                match $dynimage {
                        DynamicImage::ImageLuma8(ref $image) => $action,
                        DynamicImage::ImageLumaA8(ref $image) => $action,
                        DynamicImage::ImageRgb8(ref $image) => $action,
                        DynamicImage::ImageRgba8(ref $image) => $action,
                }
        );

        ($dynimage: expr, ref mut $image: ident -> $action: expr) => (
                match $dynimage {
                        DynamicImage::ImageLuma8(ref mut $image) => $action,
                        DynamicImage::ImageLumaA8(ref mut $image) => $action,
                        DynamicImage::ImageRgb8(ref mut $image) => $action,
                        DynamicImage::ImageRgba8(ref mut $image) => $action,
                }
        );
);

impl DynamicImage {
    /// Creates a dynamic image backed by a buffer of grey pixels.
    pub fn new_luma8(w: u32, h: u32) -> DynamicImage {
        DynamicImage::ImageLuma8(ImageBuffer::new(w, h))
    }

    /// Creates a dynamic image backed by a buffer of grey
    /// pixels with transparency.
    pub fn new_luma_a8(w: u32, h: u32) -> DynamicImage {
        DynamicImage::ImageLumaA8(ImageBuffer::new(w, h))
    }

    /// Creates a dynamic image backed by a buffer of RGB pixels.
    pub fn new_rgb8(w: u32, h: u32) -> DynamicImage {
        DynamicImage::ImageRgb8(ImageBuffer::new(w, h))
    }

    /// Creates a dynamic image backed by a buffer of RGBA pixels.
    pub fn new_rgba8(w: u32, h: u32) -> DynamicImage {
        DynamicImage::ImageRgba8(ImageBuffer::new(w, h))
    }

    /// Returns a copy of this image as an RGB image.
    pub fn to_rgb(&self) -> RgbImage {
        dynamic_map!(*self, ref p -> {
            p.convert()
        })
    }

    /// Returns a copy of this image as an RGBA image.
    pub fn to_rgba(&self) -> RgbaImage {
        dynamic_map!(*self, ref p -> {
            p.convert()
        })
    }

    /// Returns a copy of this image as a Luma image.
    pub fn to_luma(&self) -> GrayImage {
        dynamic_map!(*self, ref p -> {
            p.convert()
        })
    }

    /// Returns a copy of this image as a LumaA image.
    pub fn to_luma_alpha(&self) -> GrayAlphaImage {
        dynamic_map!(*self, ref p -> {
            p.convert()
        })
    }

    /// Return a cut out of this image delimited by the bounding rectangle.
    pub fn crop(&mut self,
                x: u32,
                y: u32,
                width: u32,
                height: u32) -> DynamicImage {

        dynamic_map!(*self, ref mut p => imageops::crop(p, x, y, width, height).to_image())
    }

    /// Return a reference to an 8bit RGB image
    pub fn as_rgb8(&self) -> Option<&RgbImage> {
        match *self {
            DynamicImage::ImageRgb8(ref p) => Some(p),
            _                              => None
        }
    }

    /// Return a mutable reference to an 8bit RGB image
    pub fn as_mut_rgb8(&mut self) -> Option<&mut RgbImage> {
        match *self {
            DynamicImage::ImageRgb8(ref mut p) => Some(p),
            _                                  => None
        }
    }

    /// Return a reference to an 8bit RGBA image
    pub fn as_rgba8(&self) -> Option<& RgbaImage> {
        match *self {
            DynamicImage::ImageRgba8(ref p) => Some(p),
            _                               => None
        }
    }

    /// Return a mutable reference to an 8bit RGBA image
    pub fn as_mut_rgba8(&mut self) -> Option<&mut RgbaImage> {
        match *self {
            DynamicImage::ImageRgba8(ref mut p) => Some(p),
            _                                   => None
        }
    }

    /// Return a reference to an 8bit Grayscale image
    pub fn as_luma8(& self) -> Option<& GrayImage> {
        match *self {
            DynamicImage::ImageLuma8(ref p) => Some(p),
            _                               => None
        }
    }

    /// Return a mutable reference to an 8bit Grayscale image
    pub fn as_mut_luma8(&mut self) -> Option<&mut GrayImage> {
        match *self {
            DynamicImage::ImageLuma8(ref mut p) => Some(p),
            _                                   => None
        }
    }

    /// Return a reference to an 8bit Grayscale image with an alpha channel
    pub fn as_luma_alpha8(&self) -> Option<& GrayAlphaImage> {
        match *self {
            DynamicImage::ImageLumaA8(ref p) => Some(p),
            _                                => None
        }
    }

    /// Return a mutable reference to an 8bit Grayscale image with an alpha channel
    pub fn as_mut_luma_alpha8(&mut self) -> Option<&mut GrayAlphaImage> {
        match *self {
            DynamicImage::ImageLumaA8(ref mut p) => Some(p),
            _                                    => None
        }
    }

    /// Return this image's pixels as a byte vector.
    pub fn raw_pixels(&self) -> Vec<u8> {
        image_to_bytes(self)
    }

    /// Return this image's color type.
    pub fn color(&self) -> color::ColorType {
        match *self {
            DynamicImage::ImageLuma8(_) => color::ColorType::Gray(8),
            DynamicImage::ImageLumaA8(_) => color::ColorType::GrayA(8),
            DynamicImage::ImageRgb8(_) => color::ColorType::RGB(8),
            DynamicImage::ImageRgba8(_) => color::ColorType::RGBA(8),
        }
    }

    /// Return a grayscale version of this image.
    pub fn grayscale(&self) -> DynamicImage {
        match *self {
            DynamicImage::ImageLuma8(ref p) => DynamicImage::ImageLuma8(p.clone()),
            DynamicImage::ImageLumaA8(ref p) => DynamicImage::ImageLuma8(imageops::grayscale(p)),
            DynamicImage::ImageRgb8(ref p) => DynamicImage::ImageLuma8(imageops::grayscale(p)),
            DynamicImage::ImageRgba8(ref p) => DynamicImage::ImageLuma8(imageops::grayscale(p)),
        }
    }

    /// Invert the colors of this image.
    /// This method operates inplace.
    pub fn invert(&mut self) {
        dynamic_map!(*self, ref mut p -> imageops::invert(p))
    }

    /// Resize this image using the specified filter algorithm.
    /// Returns a new image. The image's aspect ratio is preserved.
    /// The image is scaled to the maximum possible size that fits
    /// within the bounds specified by ```nwidth``` and ```nheight```.
    pub fn resize(&self,
                  nwidth: u32,
                  nheight: u32,
                  filter: imageops::FilterType) -> DynamicImage {

        let (width, height) = self.dimensions();

        let ratio  = width as f32 / height as f32;
        let nratio = nwidth as f32 / nheight as f32;

        let scale = if nratio > ratio {
            nheight as f32 / height as f32
        } else {
            nwidth as f32 / width as f32
        };

        let width2  = (width as f32 * scale) as u32;
        let height2 = (height as f32 * scale) as u32;

        self.resize_exact(width2, height2, filter)
    }

    /// Resize this image using the specified filter algorithm.
    /// Returns a new image. Does not preserve aspect ratio.
    /// ```nwidth``` and ```nheight``` are the new image's dimensions
    pub fn resize_exact(&self,
                        nwidth: u32,
                        nheight: u32,
                        filter: imageops::FilterType) -> DynamicImage {

        dynamic_map!(*self, ref p => imageops::resize(p, nwidth, nheight, filter))
    }

    /// Performs a Gaussian blur on this image.
    /// ```sigma``` is a measure of how much to blur by.
    pub fn blur(&self, sigma: f32) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::blur(p, sigma))
    }

    /// Performs an unsharpen mask on this image.
    /// ```sigma``` is the amount to blur the image by.
    /// ```threshold``` is a control of how much to sharpen.
    ///
    /// See <https://en.wikipedia.org/wiki/Unsharp_masking#Digital_unsharp_masking>
    pub fn unsharpen(&self, sigma: f32, threshold: i32) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::unsharpen(p, sigma, threshold))
    }

    /// Filters this image with the specified 3x3 kernel.
    pub fn filter3x3(&self, kernel: &[f32]) -> DynamicImage {
        if kernel.len() != 9 {
            panic!("filter must be 3 x 3")
        }

        dynamic_map!(*self, ref p => imageops::filter3x3(p, kernel))
    }

    /// Adjust the contrast of this image.
    /// ```contrast``` is the amount to adjust the contrast by.
    /// Negative values decrease the contrast and positive values increase the contrast.
    pub fn adjust_contrast(&self, c: f32) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::contrast(p, c))
    }

    /// Brighten the pixels of this image.
    /// ```value``` is the amount to brighten each pixel by.
    /// Negative values decrease the brightness and positive values increase it.
    pub fn brighten(&self, value: i32) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::brighten(p, value))
    }

    /// Hue rotate the supplied image.
    /// `value` is the degrees to rotate each pixel by.
    /// 0 and 360 do nothing, the rest rotates by the given degree value.
    /// just like the css webkit filter hue-rotate(180)
    pub fn huerotate(&self, value: i32) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::huerotate(p, value))
    }

    /// Flip this image vertically
    pub fn flipv(&self) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::flip_vertical(p))
    }

    /// Flip this image horizontally
    pub fn fliph(&self) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::flip_horizontal(p))
    }

    /// Rotate this image 90 degrees clockwise.
    pub fn rotate90(&self) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::rotate90(p))
    }

    /// Rotate this image 180 degrees clockwise.
    pub fn rotate180(&self) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::rotate180(p))
    }

    /// Rotate this image 270 degrees clockwise.
    pub fn rotate270(&self) -> DynamicImage {
        dynamic_map!(*self, ref p => imageops::rotate270(p))
    }

    /// Encode this image and write it to ```w```
    pub fn save<W: Write>(&self, w: &mut W, format: ImageFormat) -> ImageResult<()> {
        let bytes = self.raw_pixels();
        let (width, height) = self.dimensions();
        let color = self.color();

        match format {
            #[cfg(feature = "png_codec")]
            image::ImageFormat::PNG  => {
                let p = png::PNGEncoder::new(w);

                try!(p.encode(&bytes, width, height, color));
                Ok(())
            }
            #[cfg(feature = "ppm")]
            image::ImageFormat::PPM  => {
                let mut p = ppm::PPMEncoder::new(w);

                try!(p.encode(&bytes, width, height, color));
                Ok(())
            }

            #[cfg(feature = "jpeg")]
            image::ImageFormat::JPEG => {
                let mut j = jpeg::JPEGEncoder::new(w);

                try!(j.encode(&bytes, width, height, color));
                Ok(())
            }

            #[cfg(feature = "gif_codec")]
            image::ImageFormat::GIF => {
                let g = gif::Encoder::new(w);

                try!(g.encode(gif::Frame::from_rgba(
                    width as u16,
                    height as u16,
                    &mut *self.to_rgba().iter().cloned().collect::<Vec<u8>>()
                )));
                Ok(())
            }

            #[cfg(feature = "ico")]
            image::ImageFormat::ICO => {
                let i = ico::ICOEncoder::new(w);

                try!(i.encode(&bytes, width, height, color));
                Ok(())
            }

            #[cfg(feature = "bmp")]
            image::ImageFormat::BMP => {
                let mut b = bmp::BMPEncoder::new(w);
                try!(b.encode(&bytes, width, height, color));
                Ok(())
            }

            _ => Err(image::ImageError::UnsupportedError(
                     format!("An encoder for {:?} is not available.", format))
                 ),
        }
    }
}

#[allow(deprecated)]
impl GenericImage for DynamicImage {
    type Pixel = color::Rgba<u8>;

    fn dimensions(&self) -> (u32, u32) {
        dynamic_map!(*self, ref p -> p.dimensions())
    }

    fn bounds(&self) -> (u32, u32, u32, u32) {
        dynamic_map!(*self, ref p -> p.bounds())
    }

    fn get_pixel(&self, x: u32, y: u32) -> color::Rgba<u8> {
        dynamic_map!(*self, ref p -> p.get_pixel(x, y).to_rgba())
    }

    fn put_pixel(&mut self, x: u32, y: u32, pixel: color::Rgba<u8>) {
        match *self {
            DynamicImage::ImageLuma8(ref mut p) => p.put_pixel(x, y, pixel.to_luma()),
            DynamicImage::ImageLumaA8(ref mut p) => p.put_pixel(x, y, pixel.to_luma_alpha()),
            DynamicImage::ImageRgb8(ref mut p) => p.put_pixel(x, y, pixel.to_rgb()),
            DynamicImage::ImageRgba8(ref mut p) => p.put_pixel(x, y, pixel),
        }
    }
    /// DEPRECATED: Use iterator `pixels_mut` to blend the pixels directly.
    fn blend_pixel(&mut self, x: u32, y: u32, pixel: color::Rgba<u8>) {
        match *self {
            DynamicImage::ImageLuma8(ref mut p) => p.blend_pixel(x, y, pixel.to_luma()),
            DynamicImage::ImageLumaA8(ref mut p) => p.blend_pixel(x, y, pixel.to_luma_alpha()),
            DynamicImage::ImageRgb8(ref mut p) => p.blend_pixel(x, y, pixel.to_rgb()),
            DynamicImage::ImageRgba8(ref mut p) => p.blend_pixel(x, y, pixel),
        }
    }

    /// DEPRECATED: Do not use is function: It is unimplemented!
    fn get_pixel_mut(&mut self, _: u32, _: u32) -> &mut color::Rgba<u8> {
        unimplemented!()
    }
}


/// Decodes an image and stores it into a dynamic image
pub fn decoder_to_image<I: ImageDecoder>(codec: I) -> ImageResult<DynamicImage> {
    let mut codec = codec;

    let color  = try!(codec.colortype());
    let buf    = try!(codec.read_image());
    let (w, h) = try!(codec.dimensions());

    let image = match (color, buf) {
        (color::ColorType::RGB(8), U8(buf)) => {
            ImageBuffer::from_raw(w, h, buf).map(DynamicImage::ImageRgb8)
        }

        (color::ColorType::RGBA(8), U8(buf)) => {
            ImageBuffer::from_raw(w, h, buf).map(DynamicImage::ImageRgba8)
        }

        (color::ColorType::Gray(8), U8(buf)) => {
            ImageBuffer::from_raw(w, h, buf).map(DynamicImage::ImageLuma8)
        }

        (color::ColorType::GrayA(8), U8(buf)) => {
            ImageBuffer::from_raw(w, h, buf).map(DynamicImage::ImageLumaA8)
        }
        (color::ColorType::Gray(bit_depth), U8(ref buf)) if bit_depth == 1 || bit_depth == 2 || bit_depth == 4 => {
            // Note: this conversion assumes that the scanlines begin on byte boundaries
            let mask = (1u8 << bit_depth as usize) - 1;
            let scaling_factor = 255/((1 << bit_depth as usize) - 1);
            let skip = (w % 8)/u32::from(bit_depth);
            let row_len = w + skip;
            let p = buf
                       .iter()
                       .flat_map(|&v|
                           num_iter::range_step_inclusive(8i8-(bit_depth as i8), 0, -(bit_depth as i8))
                           .zip(iter::repeat(v))
                       )
                       // skip the pixels that can be neglected because scanlines should
                       // start at byte boundaries
                       .enumerate().filter(|&(i, _)| i % (row_len as usize) < (w as usize) ).map(|(_, p)| p)
                       .map(|(shift, pixel)|
                           (pixel & mask << shift as usize) >> shift as usize
                       )
                       .map(|pixel| pixel * scaling_factor)
                       .collect();
            ImageBuffer::from_raw(w, h, p).map(DynamicImage::ImageLuma8)
        },
        _ => return Err(image::ImageError::UnsupportedColor(color))
    };
    match image {
        Some(image) => Ok(image),
        None => Err(image::ImageError::DimensionError)
    }
}

#[allow(deprecated)]
fn image_to_bytes(image: &DynamicImage) -> Vec<u8> {
    match *image {
        // TODO: consider transmuting
        DynamicImage::ImageLuma8(ref a) => {
            a.iter().cloned().collect()
        }

        DynamicImage::ImageLumaA8(ref a) => {
            a.iter().cloned().collect()
        }

        DynamicImage::ImageRgb8(ref a)  => {
            a.iter().cloned().collect()
        }

        DynamicImage::ImageRgba8(ref a) => {
            a.iter().cloned().collect()
        }
    }
}

/// Open the image located at the path specified.
/// The image's format is determined from the path's file extension.
pub fn open<P>(path: P) -> ImageResult<DynamicImage> where P: AsRef<Path> {
    // thin wrapper function to strip generics before calling open_impl
    open_impl(path.as_ref())
}

fn open_impl(path: &Path) -> ImageResult<DynamicImage> {
    let fin = match File::open(path) {
        Ok(f)  => f,
        Err(err) => return Err(image::ImageError::IoError(err))
    };
    let fin = BufReader::new(fin);

    let ext = path.extension().and_then(|s| s.to_str())
                  .map_or("".to_string(), |s| s.to_ascii_lowercase());

    let format = match &ext[..] {
        "jpg" |
        "jpeg" => image::ImageFormat::JPEG,
        "png"  => image::ImageFormat::PNG,
        "gif"  => image::ImageFormat::GIF,
        "webp" => image::ImageFormat::WEBP,
        "tif" |
        "tiff" => image::ImageFormat::TIFF,
        "tga" => image::ImageFormat::TGA,
        "bmp" => image::ImageFormat::BMP,
        "ico" => image::ImageFormat::ICO,
        "hdr" => image::ImageFormat::HDR,
        "pbm" |
        "pam" |
        "pgm" => image::ImageFormat::PNM,
        "ppm" => image::ImageFormat::PPM,
        format => return Err(image::ImageError::UnsupportedError(format!(
            "Image format image/{:?} is not supported.",
            format
        )))
    };

    load(fin, format)
}

/// Saves the supplied buffer to a file at the path specified.
///
/// The image format is derived from the file extension. The buffer is assumed to have
/// the correct format according to the specified color type.

/// This will lead to corrupted files if the buffer contains malformed data. Currently only
/// jpeg and png files are supported.
pub fn save_buffer<P>(path: P, buf: &[u8], width: u32, height: u32, color: color::ColorType)
                      -> io::Result<()> where P: AsRef<Path> {
    // thin wrapper function to strip generics before calling save_buffer_impl
    save_buffer_impl(path.as_ref(), buf, width, height, color)
}

fn save_buffer_impl(path: &Path, buf: &[u8], width: u32, height: u32, color: color::ColorType)
                      -> io::Result<()> {
    let fout = &mut BufWriter::new(try!(File::create(path)));
    let ext = path.extension().and_then(|s| s.to_str())
                  .map_or("".to_string(), |s| s.to_ascii_lowercase());

    match &*ext {
        #[cfg(feature = "ico")]
        "ico" => ico::ICOEncoder::new(fout).encode(buf, width, height, color),
        #[cfg(feature = "jpeg")]
        "jpg" |
        "jpeg" => jpeg::JPEGEncoder::new(fout).encode(buf, width, height, color),
        #[cfg(feature = "png_codec")]
        "png"  => png::PNGEncoder::new(fout).encode(buf, width, height, color),
        #[cfg(feature = "ppm")]
        "ppm"  => ppm::PPMEncoder::new(fout).encode(buf, width, height, color),
        #[cfg(feature = "bmp")]
        "bmp" => bmp::BMPEncoder::new(fout).encode(buf, width, height, color),
        format => Err(io::Error::new(
            io::ErrorKind::InvalidInput,
            &format!("Unsupported image format image/{:?}", format)[..],
        ))
    }
}

/// Create a new image from a Reader
pub fn load<R: BufRead+Seek>(r: R, format: ImageFormat) -> ImageResult<DynamicImage> {
    match format {
        #[cfg(feature = "png_codec")]
        image::ImageFormat::PNG  => decoder_to_image(png::PNGDecoder::new(r)),
        #[cfg(feature = "gif_codec")]
        image::ImageFormat::GIF  => decoder_to_image(gif::Decoder::new(r)),
        #[cfg(feature = "jpeg")]
        image::ImageFormat::JPEG => decoder_to_image(jpeg::JPEGDecoder::new(r)),
        #[cfg(feature = "webp")]
        image::ImageFormat::WEBP => decoder_to_image(webp::WebpDecoder::new(r)),
        #[cfg(feature = "tiff")]
        image::ImageFormat::TIFF => decoder_to_image(try!(tiff::TIFFDecoder::new(r))),
        #[cfg(feature = "tga")]
        image::ImageFormat::TGA => decoder_to_image(tga::TGADecoder::new(r)),
        #[cfg(feature = "bmp")]
        image::ImageFormat::BMP => decoder_to_image(bmp::BMPDecoder::new(r)),
        #[cfg(feature = "ico")]
        image::ImageFormat::ICO => decoder_to_image(try!(ico::ICODecoder::new(r))),
        #[cfg(feature = "hdr")]
        image::ImageFormat::HDR => decoder_to_image(try!(hdr::HDRAdapter::new(BufReader::new(r)))),
        #[cfg(feature = "ppm")]
        image::ImageFormat::PPM => decoder_to_image(try!(ppm::PPMDecoder::new(BufReader::new(r)))),
        #[cfg(feature = "pnm")]
        image::ImageFormat::PNM => decoder_to_image(try!(pnm::PNMDecoder::new(BufReader::new(r)))),
        _ => Err(image::ImageError::UnsupportedError(format!("A decoder for {:?} is not available.", format))),
    }
}

static MAGIC_BYTES: [(&'static [u8], ImageFormat); 17] = [
    (b"\x89PNG\r\n\x1a\n", ImageFormat::PNG),
    (&[0xff, 0xd8, 0xff], ImageFormat::JPEG),
    (b"GIF89a", ImageFormat::GIF),
    (b"GIF87a", ImageFormat::GIF),
    (b"WEBP", ImageFormat::WEBP),
    (b"MM.*", ImageFormat::TIFF),
    (b"II*.", ImageFormat::TIFF),
    (b"BM", ImageFormat::BMP),
    (&[0, 0, 1, 0], ImageFormat::ICO),
    (b"#?RADIANCE", ImageFormat::HDR),
    (b"P1", ImageFormat::PNM),
    (b"P2", ImageFormat::PNM),
    (b"P3", ImageFormat::PNM),
    (b"P4", ImageFormat::PNM),
    (b"P5", ImageFormat::PNM),
    (b"P6", ImageFormat::PPM),
    (b"P7", ImageFormat::PNM),
];

/// Create a new image from a byte slice
///
/// Makes an educated guess about the image format.
/// TGA is not supported by this function.
pub fn load_from_memory(buffer: &[u8]) -> ImageResult<DynamicImage> {
    load_from_memory_with_format(buffer, try!(guess_format(buffer)))
}


/// Create a new image from a byte slice
#[inline(always)]
pub fn load_from_memory_with_format(buf: &[u8], format: ImageFormat) -> ImageResult<DynamicImage> {
    let b = io::Cursor::new(buf);
    load(b, format)
}

/// Guess image format from memory block
///
/// Makes an educated guess about the image format based on the Magic Bytes at the beginning.
/// TGA is not supported by this function.
/// This is not to be trusted on the validity of the whole memory block
pub fn guess_format(buffer: &[u8]) -> ImageResult<ImageFormat> {
    for &(signature, format) in &MAGIC_BYTES {
        if buffer.starts_with(signature) {
            return Ok(format);
        }
    }
    Err(image::ImageError::UnsupportedError(
        "Unsupported image format".to_string())
    )
}

#[cfg(test)]
mod bench {
    #[cfg(feature = "benchmarks")]
    use test;

    #[bench]
    #[cfg(feature = "benchmarks")]
    fn bench_conversion(b: &mut test::Bencher) {
        let a = super::DynamicImage::ImageRgb8(::ImageBuffer::new(1000, 1000));
        b.iter(|| {
            a.to_luma()
        });
        b.bytes = 1000*1000*3
    }
}

#[cfg(test)]
mod test {
    #[test]
    fn test_empty_file() {
        assert!(super::load_from_memory(b"").is_err());
    }
}