Remove SIGTYPE_LAST_NOPBS

[openttd/fttd.git] / src / screenshot.cpp

/* $Id$ */

/*
 * This file is part of OpenTTD.
 * OpenTTD 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.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */

/** @file screenshot.cpp The creation of screenshots! */

#include "stdafx.h"
#include "fileio_func.h"
#include "viewport_func.h"
#include "gfx_func.h"
#include "screenshot.h"
#include "blitter/factory.hpp"
#include "zoom_func.h"
#include "core/endian_func.hpp"
#include "saveload/saveload.h"
#include "company_func.h"
#include "strings_func.h"
#include "error.h"
#include "window_gui.h"
#include "window_func.h"
#include "map/zoneheight.h"
#include "landscape.h"

#include "table/strings.h"

static const char * const SCREENSHOT_NAME = "screenshot"; ///< Default filename of a saved screenshot.
static const char * const HEIGHTMAP_NAME  = "heightmap";  ///< Default filename of a saved heightmap.

char _screenshot_format_name[8];      ///< Extension of the current screenshot format (corresponds with #_cur_screenshot_format).
uint _num_screenshot_formats;         ///< Number of available screenshot formats.
uint _cur_screenshot_format;          ///< Index of the currently selected screenshot format in #_screenshot_formats.
static char _screenshot_name[128];    ///< Filename of the screenshot file.
char _full_screenshot_name[MAX_PATH]; ///< Pathname of the screenshot file.

/**
 * Callback function signature for generating lines of pixel data to be written to the screenshot file.
 * @param userdata Pointer to user data.
 * @param buf      Destination buffer.
 * @param y        Line number of the first line to write.
 * @param pitch    Number of pixels to write (1 byte for 8bpp, 4 bytes for 32bpp). @see Colour
 * @param n        Number of lines to write.
 */
typedef void ScreenshotCallback(void *userdata, void *buf, uint y, uint pitch, uint n);

/**
 * Function signature for a screenshot generation routine for one of the available formats.
 * @param name        Filename, including extension.
 * @param callb       Callback function for generating lines of pixels.
 * @param userdata    User data, passed on to \a callb.
 * @param w           Width of the image in pixels.
 * @param h           Height of the image in pixels.
 * @param pixelformat Bits per pixel (bpp), either 8 or 32.
 * @param palette     %Colour palette (for 8bpp images).
 * @return File was written successfully.
 */
typedef bool ScreenshotHandlerProc(const char *name, ScreenshotCallback *callb, void *userdata, uint w, uint h, int pixelformat, const Colour *palette);

/** Screenshot format information. */
struct ScreenshotFormat {
        const char *name;            ///< Name of the format.
        const char *extension;       ///< File extension.
        ScreenshotHandlerProc *proc; ///< Function for writing the screenshot.
        bool supports_32bpp;         ///< Does this format support 32bpp images?
};

/*************************************************
 **** SCREENSHOT CODE FOR WINDOWS BITMAP (.BMP)
 *************************************************/
#if defined(_MSC_VER) || defined(__WATCOMC__)
#pragma pack(push, 1)
#endif

/** BMP File Header (stored in little endian) */
struct BitmapFileHeader {
        uint16 type;
        uint32 size;
        uint32 reserved;
        uint32 off_bits;
} GCC_PACK;
assert_compile(sizeof(BitmapFileHeader) == 14);

#if defined(_MSC_VER) || defined(__WATCOMC__)
#pragma pack(pop)
#endif

/** BMP Info Header (stored in little endian) */
struct BitmapInfoHeader {
        uint32 size;
        int32 width, height;
        uint16 planes, bitcount;
        uint32 compression, sizeimage, xpels, ypels, clrused, clrimp;
};
assert_compile(sizeof(BitmapInfoHeader) == 40);

/** Format of palette data in BMP header */
struct RgbQuad {
        byte blue, green, red, reserved;
};
assert_compile(sizeof(RgbQuad) == 4);

/**
 * Generic .BMP writer
 * @param name file name including extension
 * @param callb callback used for gathering rendered image
 * @param userdata parameters forwarded to \a callb
 * @param w width in pixels
 * @param h height in pixels
 * @param pixelformat bits per pixel
 * @param palette colour palette (for 8bpp mode)
 * @return was everything ok?
 * @see ScreenshotHandlerProc
 */
static bool MakeBMPImage(const char *name, ScreenshotCallback *callb, void *userdata, uint w, uint h, int pixelformat, const Colour *palette)
{
        uint bpp; // bytes per pixel
        switch (pixelformat) {
                case 8:  bpp = 1; break;
                /* 32bpp mode is saved as 24bpp BMP */
                case 32: bpp = 3; break;
                /* Only implemented for 8bit and 32bit images so far */
                default: return false;
        }

        FILE *f = fopen(name, "wb");
        if (f == NULL) return false;

        /* Each scanline must be aligned on a 32bit boundary */
        uint bytewidth = Align(w * bpp, 4); // bytes per line in file

        /* Size of palette. Only present for 8bpp mode */
        uint pal_size = pixelformat == 8 ? sizeof(RgbQuad) * 256 : 0;

        /* Setup the file header */
        BitmapFileHeader bfh;
        bfh.type = TO_LE16('MB');
        bfh.size = TO_LE32(sizeof(BitmapFileHeader) + sizeof(BitmapInfoHeader) + pal_size + bytewidth * h);
        bfh.reserved = 0;
        bfh.off_bits = TO_LE32(sizeof(BitmapFileHeader) + sizeof(BitmapInfoHeader) + pal_size);

        /* Setup the info header */
        BitmapInfoHeader bih;
        bih.size = TO_LE32(sizeof(BitmapInfoHeader));
        bih.width = TO_LE32(w);
        bih.height = TO_LE32(h);
        bih.planes = TO_LE16(1);
        bih.bitcount = TO_LE16(bpp * 8);
        bih.compression = 0;
        bih.sizeimage = 0;
        bih.xpels = 0;
        bih.ypels = 0;
        bih.clrused = 0;
        bih.clrimp = 0;

        /* Write file header and info header */
        if (fwrite(&bfh, sizeof(bfh), 1, f) != 1 || fwrite(&bih, sizeof(bih), 1, f) != 1) {
                fclose(f);
                return false;
        }

        if (pixelformat == 8) {
                /* Convert the palette to the windows format */
                RgbQuad rq[256];
                for (uint i = 0; i < 256; i++) {
                        rq[i].red   = palette[i].r;
                        rq[i].green = palette[i].g;
                        rq[i].blue  = palette[i].b;
                        rq[i].reserved = 0;
                }
                /* Write the palette */
                if (fwrite(rq, sizeof(rq), 1, f) != 1) {
                        fclose(f);
                        return false;
                }
        }

        /* Try to use 64k of memory, store between 16 and 128 lines */
        uint maxlines = Clamp(65536 / (w * pixelformat / 8), 16, 128); // number of lines per iteration

        uint8 *buff = MallocT<uint8>(maxlines * w * pixelformat / 8); // buffer which is rendered to
        uint8 *line = AllocaM(uint8, bytewidth); // one line, stored to file
        memset(line, 0, bytewidth);

        /* Start at the bottom, since bitmaps are stored bottom up */
        do {
                uint n = min(h, maxlines);
                h -= n;

                /* Render the pixels */
                callb(userdata, buff, h, w, n);

                /* Write each line */
                while (n-- != 0) {
                        if (pixelformat == 8) {
                                /* Move to 'line', leave last few pixels in line zeroed */
                                memcpy(line, buff + n * w, w);
                        } else {
                                /* Convert from 'native' 32bpp to BMP-like 24bpp.
                                 * Works for both big and little endian machines */
                                Colour *src = ((Colour *)buff) + n * w;
                                byte *dst = line;
                                for (uint i = 0; i < w; i++) {
                                        dst[i * 3    ] = src[i].b;
                                        dst[i * 3 + 1] = src[i].g;
                                        dst[i * 3 + 2] = src[i].r;
                                }
                        }
                        /* Write to file */
                        if (fwrite(line, bytewidth, 1, f) != 1) {
                                free(buff);
                                fclose(f);
                                return false;
                        }
                }
        } while (h != 0);

        free(buff);
        fclose(f);

        return true;
}

/*********************************************************
 **** SCREENSHOT CODE FOR PORTABLE NETWORK GRAPHICS (.PNG)
 *********************************************************/
#if defined(WITH_PNG)
#include <png.h>

#ifdef PNG_TEXT_SUPPORTED
#include "rev.h"
#include "newgrf_config.h"
#include "ai/ai_info.hpp"
#include "company_base.h"
#include "base_media_base.h"
#endif /* PNG_TEXT_SUPPORTED */

static void PNGAPI png_my_error(png_structp png_ptr, png_const_charp message)
{
        DEBUG(misc, 0, "[libpng] error: %s - %s", message, (const char *)png_get_error_ptr(png_ptr));
        longjmp(png_jmpbuf(png_ptr), 1);
}

static void PNGAPI png_my_warning(png_structp png_ptr, png_const_charp message)
{
        DEBUG(misc, 1, "[libpng] warning: %s - %s", message, (const char *)png_get_error_ptr(png_ptr));
}

/**
 * Generic .PNG file image writer.
 * @param name        Filename, including extension.
 * @param callb       Callback function for generating lines of pixels.
 * @param userdata    User data, passed on to \a callb.
 * @param w           Width of the image in pixels.
 * @param h           Height of the image in pixels.
 * @param pixelformat Bits per pixel (bpp), either 8 or 32.
 * @param palette     %Colour palette (for 8bpp images).
 * @return File was written successfully.
 * @see ScreenshotHandlerProc
 */
static bool MakePNGImage(const char *name, ScreenshotCallback *callb, void *userdata, uint w, uint h, int pixelformat, const Colour *palette)
{
        png_color rq[256];
        FILE *f;
        uint i, y, n;
        uint maxlines;
        uint bpp = pixelformat / 8;
        png_structp png_ptr;
        png_infop info_ptr;

        /* only implemented for 8bit and 32bit images so far. */
        if (pixelformat != 8 && pixelformat != 32) return false;

        f = fopen(name, "wb");
        if (f == NULL) return false;

        png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, const_cast<char *>(name), png_my_error, png_my_warning);

        if (png_ptr == NULL) {
                fclose(f);
                return false;
        }

        info_ptr = png_create_info_struct(png_ptr);
        if (info_ptr == NULL) {
                png_destroy_write_struct(&png_ptr, (png_infopp)NULL);
                fclose(f);
                return false;
        }

        if (setjmp(png_jmpbuf(png_ptr))) {
                png_destroy_write_struct(&png_ptr, &info_ptr);
                fclose(f);
                return false;
        }

        png_init_io(png_ptr, f);

        png_set_filter(png_ptr, 0, PNG_FILTER_NONE);

        png_set_IHDR(png_ptr, info_ptr, w, h, 8, pixelformat == 8 ? PNG_COLOR_TYPE_PALETTE : PNG_COLOR_TYPE_RGB,
                PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);

#ifdef PNG_TEXT_SUPPORTED
        /* Try to add some game metadata to the PNG screenshot so
         * it's more useful for debugging and archival purposes. */
        png_text_struct text[2];
        memset(text, 0, sizeof(text));
        text[0].key = const_cast<char *>("Software");
        text[0].text = const_cast<char *>(_openttd_revision);
        text[0].text_length = strlen(_openttd_revision);
        text[0].compression = PNG_TEXT_COMPRESSION_NONE;

        char buf[8192];
        char *p = buf;
        p += seprintf(p, lastof(buf), "Graphics set: %s (%u)\n", BaseGraphics::GetUsedSet()->name, BaseGraphics::GetUsedSet()->version);
        p = strecpy(p, "NewGRFs:\n", lastof(buf));
        for (const GRFConfig *c = _game_mode == GM_MENU ? NULL : _grfconfig; c != NULL; c = c->next) {
                p += seprintf(p, lastof(buf), "%08X ", BSWAP32(c->ident.grfid));
                p = md5sumToString(p, lastof(buf), c->ident.md5sum);
                p += seprintf(p, lastof(buf), " %s\n", c->filename);
        }
        p = strecpy(p, "\nCompanies:\n", lastof(buf));
        const Company *c;
        FOR_ALL_COMPANIES(c) {
                if (c->ai_info == NULL) {
                        p += seprintf(p, lastof(buf), "%2i: Human\n", (int)c->index);
                } else {
                        p += seprintf(p, lastof(buf), "%2i: %s (v%d)\n", (int)c->index, c->ai_info->GetName(), c->ai_info->GetVersion());
                }
        }
        text[1].key = const_cast<char *>("Description");
        text[1].text = buf;
        text[1].text_length = p - buf;
        text[1].compression = PNG_TEXT_COMPRESSION_zTXt;
        png_set_text(png_ptr, info_ptr, text, 2);
#endif /* PNG_TEXT_SUPPORTED */

        if (pixelformat == 8) {
                /* convert the palette to the .PNG format. */
                for (i = 0; i != 256; i++) {
                        rq[i].red   = palette[i].r;
                        rq[i].green = palette[i].g;
                        rq[i].blue  = palette[i].b;
                }

                png_set_PLTE(png_ptr, info_ptr, rq, 256);
        }

        png_write_info(png_ptr, info_ptr);
        png_set_flush(png_ptr, 512);

        if (pixelformat == 32) {
                png_color_8 sig_bit;

                /* Save exact colour/alpha resolution */
                sig_bit.alpha = 0;
                sig_bit.blue  = 8;
                sig_bit.green = 8;
                sig_bit.red   = 8;
                sig_bit.gray  = 8;
                png_set_sBIT(png_ptr, info_ptr, &sig_bit);

#if TTD_ENDIAN == TTD_LITTLE_ENDIAN
                png_set_bgr(png_ptr);
                png_set_filler(png_ptr, 0, PNG_FILLER_AFTER);
#else
                png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
#endif /* TTD_ENDIAN == TTD_LITTLE_ENDIAN */
        }

        /* use by default 64k temp memory */
        maxlines = Clamp(65536 / w, 16, 128);

        /* now generate the bitmap bits */
        void *buff = CallocT<uint8>(w * maxlines * bpp); // by default generate 128 lines at a time.

        y = 0;
        do {
                /* determine # lines to write */
                n = min(h - y, maxlines);

                /* render the pixels into the buffer */
                callb(userdata, buff, y, w, n);
                y += n;

                /* write them to png */
                for (i = 0; i != n; i++) {
                        png_write_row(png_ptr, (png_bytep)buff + i * w * bpp);
                }
        } while (y != h);

        png_write_end(png_ptr, info_ptr);
        png_destroy_write_struct(&png_ptr, &info_ptr);

        free(buff);
        fclose(f);
        return true;
}
#endif /* WITH_PNG */


/*************************************************
 **** SCREENSHOT CODE FOR ZSOFT PAINTBRUSH (.PCX)
 *************************************************/

/** Definition of a PCX file header. */
struct PcxHeader {
        byte manufacturer;
        byte version;
        byte rle;
        byte bpp;
        uint32 unused;
        uint16 xmax, ymax;
        uint16 hdpi, vdpi;
        byte pal_small[16 * 3];
        byte reserved;
        byte planes;
        uint16 pitch;
        uint16 cpal;
        uint16 width;
        uint16 height;
        byte filler[54];
};
assert_compile(sizeof(PcxHeader) == 128);

/**
 * Generic .PCX file image writer.
 * @param name        Filename, including extension.
 * @param callb       Callback function for generating lines of pixels.
 * @param userdata    User data, passed on to \a callb.
 * @param w           Width of the image in pixels.
 * @param h           Height of the image in pixels.
 * @param pixelformat Bits per pixel (bpp), either 8 or 32.
 * @param palette     %Colour palette (for 8bpp images).
 * @return File was written successfully.
 * @see ScreenshotHandlerProc
 */
static bool MakePCXImage(const char *name, ScreenshotCallback *callb, void *userdata, uint w, uint h, int pixelformat, const Colour *palette)
{
        FILE *f;
        uint maxlines;
        uint y;
        PcxHeader pcx;
        bool success;

        if (pixelformat == 32) {
                DEBUG(misc, 0, "Can't convert a 32bpp screenshot to PCX format. Please pick another format.");
                return false;
        }
        if (pixelformat != 8 || w == 0) return false;

        f = fopen(name, "wb");
        if (f == NULL) return false;

        memset(&pcx, 0, sizeof(pcx));

        /* setup pcx header */
        pcx.manufacturer = 10;
        pcx.version = 5;
        pcx.rle = 1;
        pcx.bpp = 8;
        pcx.xmax = TO_LE16(w - 1);
        pcx.ymax = TO_LE16(h - 1);
        pcx.hdpi = TO_LE16(320);
        pcx.vdpi = TO_LE16(320);

        pcx.planes = 1;
        pcx.cpal = TO_LE16(1);
        pcx.width = pcx.pitch = TO_LE16(w);
        pcx.height = TO_LE16(h);

        /* write pcx header */
        if (fwrite(&pcx, sizeof(pcx), 1, f) != 1) {
                fclose(f);
                return false;
        }

        /* use by default 64k temp memory */
        maxlines = Clamp(65536 / w, 16, 128);

        /* now generate the bitmap bits */
        uint8 *buff = CallocT<uint8>(w * maxlines); // by default generate 128 lines at a time.

        y = 0;
        do {
                /* determine # lines to write */
                uint n = min(h - y, maxlines);
                uint i;

                /* render the pixels into the buffer */
                callb(userdata, buff, y, w, n);
                y += n;

                /* write them to pcx */
                for (i = 0; i != n; i++) {
                        const uint8 *bufp = buff + i * w;
                        byte runchar = bufp[0];
                        uint runcount = 1;
                        uint j;

                        /* for each pixel... */
                        for (j = 1; j < w; j++) {
                                uint8 ch = bufp[j];

                                if (ch != runchar || runcount >= 0x3f) {
                                        if (runcount > 1 || (runchar & 0xC0) == 0xC0) {
                                                if (fputc(0xC0 | runcount, f) == EOF) {
                                                        free(buff);
                                                        fclose(f);
                                                        return false;
                                                }
                                        }
                                        if (fputc(runchar, f) == EOF) {
                                                free(buff);
                                                fclose(f);
                                                return false;
                                        }
                                        runcount = 0;
                                        runchar = ch;
                                }
                                runcount++;
                        }

                        /* write remaining bytes.. */
                        if (runcount > 1 || (runchar & 0xC0) == 0xC0) {
                                if (fputc(0xC0 | runcount, f) == EOF) {
                                        free(buff);
                                        fclose(f);
                                        return false;
                                }
                        }
                        if (fputc(runchar, f) == EOF) {
                                free(buff);
                                fclose(f);
                                return false;
                        }
                }
        } while (y != h);

        free(buff);

        /* write 8-bit colour palette */
        if (fputc(12, f) == EOF) {
                fclose(f);
                return false;
        }

        /* Palette is word-aligned, copy it to a temporary byte array */
        byte tmp[256 * 3];

        for (uint i = 0; i < 256; i++) {
                tmp[i * 3 + 0] = palette[i].r;
                tmp[i * 3 + 1] = palette[i].g;
                tmp[i * 3 + 2] = palette[i].b;
        }
        success = fwrite(tmp, sizeof(tmp), 1, f) == 1;

        fclose(f);

        return success;
}

/*************************************************
 **** GENERIC SCREENSHOT CODE
 *************************************************/

/** Available screenshot formats. */
static const ScreenshotFormat _screenshot_formats[] = {
#if defined(WITH_PNG)
        {"PNG", "png", &MakePNGImage, true},
#endif
        {"BMP", "bmp", &MakeBMPImage, true},
        {"PCX", "pcx", &MakePCXImage, false},
};

/** Get filename extension of current screenshot file format. */
const char *GetCurrentScreenshotExtension()
{
        return _screenshot_formats[_cur_screenshot_format].extension;
}

/** Initialize screenshot format information on startup, with #_screenshot_format_name filled from the loadsave code. */
void InitializeScreenshotFormats()
{
        uint j = 0;
        for (uint i = 0; i < lengthof(_screenshot_formats); i++) {
                if (!strcmp(_screenshot_format_name, _screenshot_formats[i].extension)) {
                        j = i;
                        break;
                }
        }
        _cur_screenshot_format = j;
        _num_screenshot_formats = lengthof(_screenshot_formats);
}

/**
 * Give descriptive name of the screenshot format.
 * @param i Number of the screenshot format.
 * @return String constant describing the format.
 */
const char *GetScreenshotFormatDesc(int i)
{
        return _screenshot_formats[i].name;
}

/**
 * Determine whether a certain screenshot format support 32bpp images.
 * @param i Number of the screenshot format.
 * @return true if 32bpp is supported.
 */
bool GetScreenshotFormatSupports_32bpp(int i)
{
        return _screenshot_formats[i].supports_32bpp;
}

/**
 * Set the screenshot format to use.
 * @param i Number of the format.
 */
void SetScreenshotFormat(uint i)
{
        assert(i < _num_screenshot_formats);
        _cur_screenshot_format = i;
        strecpy(_screenshot_format_name, _screenshot_formats[i].extension, lastof(_screenshot_format_name));
}

/**
 * Callback of the screenshot generator that dumps the current video buffer.
 * @see ScreenshotCallback
 */
static void CurrentScreenCallback(void *userdata, void *buf, uint y, uint pitch, uint n)
{
        Blitter *blitter = BlitterFactory::GetCurrentBlitter();
        void *src = blitter->MoveTo(_screen.dst_ptr, 0, y);
        blitter->CopyImageToBuffer(src, buf, _screen.width, n, pitch);
}

/**
 * generate a large piece of the world
 * @param userdata Viewport area to draw
 * @param buf Videobuffer with same bitdepth as current blitter
 * @param y First line to render
 * @param pitch Pitch of the videobuffer
 * @param n Number of lines to render
 */
static void LargeWorldCallback(void *userdata, void *buf, uint y, uint pitch, uint n)
{
        ViewPort *vp = (ViewPort *)userdata;
        DrawPixelInfo dpi, *old_dpi;
        int wx, left;

        /* We are no longer rendering to the screen */
        DrawPixelInfo old_screen = _screen;
        bool old_disable_anim = _screen_disable_anim;

        _screen.dst_ptr = buf;
        _screen.width = pitch;
        _screen.height = n;
        _screen.pitch = pitch;
        _screen_disable_anim = true;

        old_dpi = _cur_dpi;
        _cur_dpi = &dpi;

        dpi.dst_ptr = buf;
        dpi.height = n;
        dpi.width = vp->width;
        dpi.pitch = pitch;
        dpi.zoom = ZOOM_LVL_WORLD_SCREENSHOT;
        dpi.left = 0;
        dpi.top = y;

        /* Render viewport in blocks of 1600 pixels width */
        left = 0;
        while (vp->width - left != 0) {
                wx = min(vp->width - left, 1600);
                left += wx;

                ViewportDoDraw(vp,
                        ScaleByZoom(left - wx - vp->left, vp->zoom) + vp->virtual_left,
                        ScaleByZoom(y - vp->top, vp->zoom) + vp->virtual_top,
                        ScaleByZoom(left - vp->left, vp->zoom) + vp->virtual_left,
                        ScaleByZoom((y + n) - vp->top, vp->zoom) + vp->virtual_top
                );
        }

        _cur_dpi = old_dpi;

        /* Switch back to rendering to the screen */
        _screen = old_screen;
        _screen_disable_anim = old_disable_anim;
}

/**
 * Construct a pathname for a screenshot file.
 * @param default_fn Default filename.
 * @param ext        Extension to use.
 * @param crashlog   Create path for crash.png
 * @return Pathname for a screenshot file.
 */
static const char *MakeScreenshotName(const char *default_fn, const char *ext, bool crashlog = false)
{
        bool generate = StrEmpty(_screenshot_name);

        if (generate) {
                if (_game_mode == GM_EDITOR || _game_mode == GM_MENU || _local_company == COMPANY_SPECTATOR) {
                        strecpy(_screenshot_name, default_fn, lastof(_screenshot_name));
                } else {
                        GenerateDefaultSaveName(_screenshot_name, lastof(_screenshot_name));
                }
        }

        /* Add extension to screenshot file */
        size_t len = strlen(_screenshot_name);
        snprintf(&_screenshot_name[len], lengthof(_screenshot_name) - len, ".%s", ext);

        const char *screenshot_dir = crashlog ? _personal_dir : FiosGetScreenshotDir();

        for (uint serial = 1;; serial++) {
                if (snprintf(_full_screenshot_name, lengthof(_full_screenshot_name), "%s%s", screenshot_dir, _screenshot_name) >= (int)lengthof(_full_screenshot_name)) {
                        /* We need more characters than MAX_PATH -> end with error */
                        _full_screenshot_name[0] = '\0';
                        break;
                }
                if (!generate) break; // allow overwriting of non-automatic filenames
                if (!FileExists(_full_screenshot_name)) break;
                /* If file exists try another one with same name, but just with a higher index */
                snprintf(&_screenshot_name[len], lengthof(_screenshot_name) - len, "#%u.%s", serial, ext);
        }

        return _full_screenshot_name;
}

/** Make a screenshot of the current screen. */
static bool MakeSmallScreenshot(bool crashlog)
{
        const ScreenshotFormat *sf = _screenshot_formats + _cur_screenshot_format;
        return sf->proc(MakeScreenshotName(SCREENSHOT_NAME, sf->extension, crashlog), CurrentScreenCallback, NULL, _screen.width, _screen.height,
                        BlitterFactory::GetCurrentBlitter()->GetScreenDepth(), _cur_palette.palette);
}

/**
 * Configure a ViewPort for rendering (a part of) the map into a screenshot.
 * @param t Screenshot type
 * @param [out] vp Result viewport
 */
void SetupScreenshotViewport(ScreenshotType t, ViewPort *vp)
{
        /* Determine world coordinates of screenshot */
        if (t == SC_WORLD) {
                vp->zoom = ZOOM_LVL_WORLD_SCREENSHOT;

                TileIndex north_tile = _settings_game.construction.freeform_edges ? TileXY(1, 1) : TileXY(0, 0);
                TileIndex south_tile = MapSize() - 1;

                /* We need to account for a hill or high building at tile 0,0. */
                int extra_height_top = TilePixelHeight(north_tile) + 150;
                /* If there is a hill at the bottom don't create a large black area. */
                int reclaim_height_bottom = TilePixelHeight(south_tile);

                vp->virtual_left   = RemapCoords(TileX(south_tile) * TILE_SIZE, TileY(north_tile) * TILE_SIZE, 0).x;
                vp->virtual_top    = RemapCoords(TileX(north_tile) * TILE_SIZE, TileY(north_tile) * TILE_SIZE, extra_height_top).y;
                vp->virtual_width  = RemapCoords(TileX(north_tile) * TILE_SIZE, TileY(south_tile) * TILE_SIZE, 0).x                     - vp->virtual_left + 1;
                vp->virtual_height = RemapCoords(TileX(south_tile) * TILE_SIZE, TileY(south_tile) * TILE_SIZE, reclaim_height_bottom).y - vp->virtual_top  + 1;
        } else {
                vp->zoom = (t == SC_ZOOMEDIN) ? _settings_client.gui.zoom_min : ZOOM_LVL_VIEWPORT;

                Window *w = FindWindowById(WC_MAIN_WINDOW, 0);
                vp->virtual_left   = w->viewport->virtual_left;
                vp->virtual_top    = w->viewport->virtual_top;
                vp->virtual_width  = w->viewport->virtual_width;
                vp->virtual_height = w->viewport->virtual_height;
        }

        /* Compute pixel coordinates */
        vp->left = 0;
        vp->top = 0;
        vp->width  = UnScaleByZoom(vp->virtual_width,  vp->zoom);
        vp->height = UnScaleByZoom(vp->virtual_height, vp->zoom);
        vp->overlay = NULL;
}

/**
 * Make a screenshot of the map.
 * @param t Screenshot type: World or viewport screenshot
 * @return true on success
 */
static bool MakeLargeWorldScreenshot(ScreenshotType t)
{
        ViewPort vp;
        SetupScreenshotViewport(t, &vp);

        const ScreenshotFormat *sf = _screenshot_formats + _cur_screenshot_format;
        return sf->proc(MakeScreenshotName(SCREENSHOT_NAME, sf->extension), LargeWorldCallback, &vp, vp.width, vp.height,
                        BlitterFactory::GetCurrentBlitter()->GetScreenDepth(), _cur_palette.palette);
}

/**
 * Callback for generating a heightmap. Supports 8bpp grayscale only.
 * @param userdata Pointer to user data.
 * @param buf      Destination buffer.
 * @param y        Line number of the first line to write.
 * @param pitch    Number of pixels to write (1 byte for 8bpp, 4 bytes for 32bpp). @see Colour
 * @param n        Number of lines to write.
 * @see ScreenshotCallback
 */
static void HeightmapCallback(void *userdata, void *buffer, uint y, uint pitch, uint n)
{
        byte *buf = (byte *)buffer;
        while (n > 0) {
                TileIndex ti = TileXY(MapMaxX(), y);
                for (uint x = MapMaxX(); true; x--) {
                        *buf = 16 * TileHeight(ti);
                        buf++;
                        if (x == 0) break;
                        ti = TILE_ADDXY(ti, -1, 0);
                }
                y++;
                n--;
        }
}

/**
 * Make a heightmap of the current map.
 * @param filename Filename to use for saving.
 */
bool MakeHeightmapScreenshot(const char *filename)
{
        Colour palette[256];
        for (uint i = 0; i < lengthof(palette); i++) {
                palette[i].a = 0xff;
                palette[i].r = i;
                palette[i].g = i;
                palette[i].b = i;
        }
        const ScreenshotFormat *sf = _screenshot_formats + _cur_screenshot_format;
        return sf->proc(filename, HeightmapCallback, NULL, MapSizeX(), MapSizeY(), 8, palette);
}

/**
 * Make an actual screenshot.
 * @param t    the type of screenshot to make.
 * @param name the name to give to the screenshot.
 * @return true iff the screenshot was made successfully
 */
bool MakeScreenshot(ScreenshotType t, const char *name)
{
        if (t == SC_VIEWPORT) {
                /* First draw the dirty parts of the screen and only then change the name
                 * of the screenshot. This way the screenshot will always show the name
                 * of the previous screenshot in the 'successful' message instead of the
                 * name of the new screenshot (or an empty name). */
                UndrawMouseCursor();
                DrawDirtyBlocks();
        }

        _screenshot_name[0] = '\0';
        if (name != NULL) strecpy(_screenshot_name, name, lastof(_screenshot_name));

        bool ret;
        switch (t) {
                case SC_VIEWPORT:
                        ret = MakeSmallScreenshot(false);
                        break;

                case SC_CRASHLOG:
                        ret = MakeSmallScreenshot(true);
                        break;

                case SC_ZOOMEDIN:
                case SC_DEFAULTZOOM:
                case SC_WORLD:
                        ret = MakeLargeWorldScreenshot(t);
                        break;

                case SC_HEIGHTMAP: {
                        const ScreenshotFormat *sf = _screenshot_formats + _cur_screenshot_format;
                        ret = MakeHeightmapScreenshot(MakeScreenshotName(HEIGHTMAP_NAME, sf->extension));
                        break;
                }

                default:
                        NOT_REACHED();
        }

        if (ret) {
                SetDParamStr(0, _screenshot_name);
                ShowErrorMessage(STR_MESSAGE_SCREENSHOT_SUCCESSFULLY, INVALID_STRING_ID, WL_WARNING);
        } else {
                ShowErrorMessage(STR_ERROR_SCREENSHOT_FAILED, INVALID_STRING_ID, WL_ERROR);
        }

        return ret;
}