path: root/frontends/cocoa/bitmap.m

/*
 * Copyright 2011 Sven Weidauer <sven.weidauer@gmail.com>
 *
 * This file is part of NetSurf, http://www.netsurf-browser.org/
 *
 * NetSurf is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * NetSurf is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * \file
 * Cocoa implementation of bitmap operations.
 */

#import <Cocoa/Cocoa.h>

#import "netsurf/browser_window.h"
#import "netsurf/plotters.h"
#import "netsurf/bitmap.h"
#import "netsurf/content.h"

#import "cocoa/plotter.h"
#import "cocoa/bitmap.h"

#import "cocoa/arc.h"

#define BITS_PER_SAMPLE (8)
#define SAMPLES_PER_PIXEL (4)
#define BITS_PER_PIXEL (BITS_PER_SAMPLE * SAMPLES_PER_PIXEL)
#define BYTES_PER_PIXEL (BITS_PER_PIXEL / 8)
#define RED_OFFSET (0)
#define GREEN_OFFSET (1)
#define BLUE_OFFSET (2)
#define ALPHA_OFFSET (3)

static CGImageRef cocoa_prepare_bitmap(void *bitmap);

static inline NSMapTable *cocoa_get_bitmap_cache(void)
{
    static NSMapTable *cache = nil;
    if (cache == nil) {
        cache = NSCreateMapTable(NSNonOwnedPointerMapKeyCallBacks, NSNonOwnedPointerMapValueCallBacks, 0);
    }
    return cache;
}

static inline NSBitmapImageRep *get_bitmap(void *bitmap) {
    NSCParameterAssert(bitmap);
    return (__bridge NSBitmapImageRep *)bitmap;
}

static int bitmap_get_width(void *bitmap)
{
    return (int)get_bitmap(bitmap).pixelsWide;
}

static int bitmap_get_height(void *bitmap)
{
    return (int)get_bitmap(bitmap).pixelsHigh;
}

static bool bitmap_get_opaque(void *bitmap)
{
    return get_bitmap(bitmap).isOpaque;
}

static void bitmap_destroy(void *bitmap)
{
    NSCParameterAssert(NULL != bitmap);

    cocoa_bitmap_modified(bitmap);
    arc_release(bitmap);
}

static void *bitmap_create(int width, int height, unsigned int state)
{
    NSBitmapImageRep *bmp = [[NSBitmapImageRep alloc]
        initWithBitmapDataPlanes:NULL
                      pixelsWide:width
                      pixelsHigh:height
                   bitsPerSample:BITS_PER_SAMPLE
                 samplesPerPixel:SAMPLES_PER_PIXEL
                        hasAlpha:YES
                        isPlanar:NO
                  colorSpaceName:NSDeviceRGBColorSpace
                    bitmapFormat:NSAlphaNonpremultipliedBitmapFormat
                     bytesPerRow:BYTES_PER_PIXEL * width
                    bitsPerPixel:BITS_PER_PIXEL];

    return arc_retain(bmp);
}

static void bitmap_set_opaque(void *bitmap, bool opaque)
{
    get_bitmap(bitmap).opaque = opaque ? YES : NO;
}

static unsigned char *bitmap_get_buffer(void *bitmap)
{
    return get_bitmap(bitmap).bitmapData;
}

static size_t bitmap_get_rowstride(void *bitmap)
{
    return get_bitmap(bitmap).bytesPerRow;
}

static size_t bitmap_get_bpp(void *bitmap)
{
    return get_bitmap(bitmap).bitsPerPixel / 8;
}

static bool bitmap_test_opaque(void *bitmap)
{
    NSCParameterAssert(bitmap_get_bpp(bitmap) == BYTES_PER_PIXEL);

    unsigned char *buf = bitmap_get_buffer(bitmap);

    const size_t height = bitmap_get_height(bitmap);
    const size_t width = bitmap_get_width(bitmap);

    const size_t line_step = bitmap_get_rowstride(bitmap) - BYTES_PER_PIXEL * width;

    for (size_t y = 0; y < height; y++) {
        for (size_t x = 0; x < height; x++) {
            if (buf[ALPHA_OFFSET] != 0xFF)
                return false;
            buf += BYTES_PER_PIXEL;
        }
        buf += line_step;
    }

    return true;
}

static bool bitmap_save(void *bitmap, const char *path, unsigned flags)
{
    NSData *tiff = get_bitmap(bitmap).TIFFRepresentation;
    return [tiff writeToFile:@(path) atomically:YES];
}

void cocoa_bitmap_modified(void *bitmap)
{
    NSMapTable *cache = cocoa_get_bitmap_cache();
    CGImageRef image = NSMapGet(cache, bitmap);
    if (NULL != image) {
        CGImageRelease(image);
        NSMapRemove(cache, bitmap);
    }
}

CGImageRef cocoa_get_cgimage(void *bitmap)
{
    NSMapTable *cache = cocoa_get_bitmap_cache();

    CGImageRef result = NSMapGet(cache, bitmap);
    if (NULL == result) {
        result = cocoa_prepare_bitmap(bitmap);
        NSMapInsertKnownAbsent(cache, bitmap, result);
    }

    return result;
}

static CGImageRef cocoa_prepare_bitmap(void *bitmap)
{
    NSBitmapImageRep *bmp = get_bitmap(bitmap);

    size_t w = bmp.pixelsWide;
    size_t h = bmp.pixelsHigh;

    CGImageRef original = bmp.CGImage;

    if (h <= 1) {
        return CGImageRetain(original);
    }

    void *data = malloc(4 * w * h);

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
    CGContextRef context = CGBitmapContextCreate(data, w, h, BITS_PER_SAMPLE,
        BYTES_PER_PIXEL * w, colorSpace,
        [bmp isOpaque] ? kCGImageAlphaNoneSkipLast
                       : kCGImageAlphaPremultipliedLast);
    CGColorSpaceRelease(colorSpace);

    CGContextTranslateCTM(context, 0.0, h);
    CGContextScaleCTM(context, 1.0, -1.0);

    CGRect rect = CGRectMake(0, 0, w, h);
    CGContextClearRect(context, rect);
    CGContextDrawImage(context, rect, original);

    CGImageRef result = CGBitmapContextCreateImage(context);

    CGContextRelease(context);
    free(data);

    return result;
}

static nserror bitmap_render(struct bitmap *bitmap, struct hlcache_handle *content)
{
    int bwidth = bitmap_get_width(bitmap);
    int bheight = bitmap_get_height(bitmap);

    struct redraw_context ctx = {
        .interactive = false,
        .background_images = true,
        .plot = &cocoa_plotters
    };

    CGColorSpaceRef cspace = CGColorSpaceCreateWithName(kCGColorSpaceGenericRGB);
    CGContextRef bitmapContext = CGBitmapContextCreate(bitmap_get_buffer(bitmap),
        bwidth, bheight,
        bitmap_get_bpp(bitmap) * 8 / 4,
        bitmap_get_rowstride(bitmap),
        cspace, kCGImageAlphaNoneSkipLast);
    CGColorSpaceRelease(cspace);

    int width = MIN(content_get_width(content), 1024);
    int height = ((width * bheight) + bwidth / 2) / bwidth;

    CGContextTranslateCTM(bitmapContext, 0, bheight);
    CGContextScaleCTM(bitmapContext, (CGFloat)bwidth / width, -(CGFloat)bheight / height);

    [NSGraphicsContext setCurrentContext:[NSGraphicsContext graphicsContextWithGraphicsPort:bitmapContext flipped:YES]];

    content_scaled_redraw(content, width, height, &ctx);

    [NSGraphicsContext setCurrentContext:nil];
    CGContextRelease(bitmapContext);

    cocoa_bitmap_modified(bitmap);

    return NSERROR_OK;
}

static struct gui_bitmap_table bitmap_table = {
    .create = bitmap_create,
    .destroy = bitmap_destroy,
    .set_opaque = bitmap_set_opaque,
    .get_opaque = bitmap_get_opaque,
    .test_opaque = bitmap_test_opaque,
    .get_buffer = bitmap_get_buffer,
    .get_rowstride = bitmap_get_rowstride,
    .get_width = bitmap_get_width,
    .get_height = bitmap_get_height,
    .get_bpp = bitmap_get_bpp,
    .save = bitmap_save,
    .modified = cocoa_bitmap_modified,
    .render = bitmap_render,
};

struct gui_bitmap_table *cocoa_bitmap_table = &bitmap_table;