建档

Library/SDL2_image-2.5.2/IMG_svg.c

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+/*
+  SDL_image:  An example image loading library for use with SDL
+  Copyright (C) 1997-2022 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+
+/* This is an SVG image file loading framework, based on Nano SVG:
+ * https://github.com/memononen/nanosvg
+ */
+
+#include "SDL_image.h"
+
+#ifdef LOAD_SVG
+
+#if !SDL_VERSION_ATLEAST(2, 0, 16)
+/* SDL_roundf() is available starting with 2.0.16 */
+static float SDLCALL SDL_roundf(float x)
+{
+    return (x >= 0.0f) ? SDL_floorf(x + 0.5f) : SDL_ceilf(x - 0.5f);
+}
+#endif /* SDL 2.0.16 */
+
+/* Replace C runtime functions with SDL C runtime functions for building on Windows */
+#define free    SDL_free
+#define malloc  SDL_malloc
+#undef memcpy
+#define memcpy  SDL_memcpy
+#undef memset
+#define memset  SDL_memset
+#define qsort   SDL_qsort
+#define realloc SDL_realloc
+#define sscanf  SDL_sscanf
+#undef strchr
+#define strchr  SDL_strchr
+#undef strcmp
+#define strcmp  SDL_strcmp
+#undef strncmp
+#define strncmp SDL_strncmp
+#undef strncpy
+#define strncpy SDL_strlcpy
+#define strlen  SDL_strlen
+#define strstr  SDL_strstr
+#define strtol  SDL_strtol
+#define strtoll SDL_strtoll
+
+#define acosf   SDL_acosf
+#define atan2f  SDL_atan2f
+#define cosf    SDL_cosf
+#define ceilf   SDL_ceilf
+#define fabs    SDL_fabs
+#define fabsf   SDL_fabsf
+#define floorf  SDL_floorf
+#define fmodf   SDL_fmodf
+#define pow     SDL_pow
+#define sinf    SDL_sinf
+#define sqrt    SDL_sqrt
+#define sqrtf   SDL_sqrtf
+#define tanf    SDL_tanf
+#define roundf  SDL_roundf
+#ifndef FLT_MAX
+#define FLT_MAX     3.402823466e+38F
+#endif
+#undef HAVE_STDIO_H
+
+#define NSVG_EXPORT static
+#define NANOSVG_IMPLEMENTATION
+#include "nanosvg.h"
+#define NANOSVGRAST_IMPLEMENTATION
+#include "nanosvgrast.h"
+
+/* See if an image is contained in a data source */
+int IMG_isSVG(SDL_RWops *src)
+{
+    Sint64 start;
+    int is_SVG;
+    char magic[4096];
+    size_t magic_len;
+
+    if (!src)
+        return 0;
+    start = SDL_RWtell(src);
+    is_SVG = 0;
+    magic_len = SDL_RWread(src, magic, 1, sizeof(magic) - 1);
+    magic[magic_len] = '\0';
+    if (SDL_strstr(magic, "<svg")) {
+        is_SVG = 1;
+    }
+    SDL_RWseek(src, start, RW_SEEK_SET);
+    return(is_SVG);
+}
+
+/* Load a SVG type image from an SDL datasource */
+SDL_Surface *IMG_LoadSizedSVG_RW(SDL_RWops *src, int width, int height)
+{
+    char *data;
+    struct NSVGimage *image;
+    struct NSVGrasterizer *rasterizer;
+    SDL_Surface *surface = NULL;
+    float scale = 1.0f;
+
+    data = (char *)SDL_LoadFile_RW(src, NULL, SDL_FALSE);
+    if (!data) {
+        return NULL;
+    }
+
+    /* For now just use default units of pixels at 96 DPI */
+    image = nsvgParse(data, "px", 96.0f);
+    SDL_free(data);
+    if (!image || image->width <= 0.0f || image->height <= 0.0f) {
+        IMG_SetError("Couldn't parse SVG image");
+        return NULL;
+    }
+
+    rasterizer = nsvgCreateRasterizer();
+    if (!rasterizer) {
+        IMG_SetError("Couldn't create SVG rasterizer");
+        nsvgDelete(image);
+        return NULL;
+    }
+
+    if (width > 0 && height > 0) {
+        float scale_x = (float)width / image->width;
+        float scale_y = (float)height / image->height;
+
+        scale = SDL_min(scale_x, scale_y);
+    } else if (width > 0) {
+        scale = (float)width / image->width;
+    } else if (height > 0) {
+        scale = (float)height / image->height;
+    } else {
+        scale = 1.0f;
+    }
+
+    surface = SDL_CreateRGBSurfaceWithFormat(0,
+                                             (int)SDL_ceilf(image->width * scale),
+                                             (int)SDL_ceilf(image->height * scale),
+                                             32,
+                                             SDL_PIXELFORMAT_RGBA32);
+
+    if (!surface) {
+        nsvgDeleteRasterizer(rasterizer);
+        nsvgDelete(image);
+        return NULL;
+    }
+
+    nsvgRasterize(rasterizer, image, 0.0f, 0.0f, scale, (unsigned char *)surface->pixels, surface->w, surface->h, surface->pitch);
+    nsvgDeleteRasterizer(rasterizer);
+    nsvgDelete(image);
+
+    return surface;
+}
+
+#else
+#if _MSC_VER >= 1300
+#pragma warning(disable : 4100) /* warning C4100: 'op' : unreferenced formal parameter */
+#endif
+
+/* See if an image is contained in a data source */
+int IMG_isSVG(SDL_RWops *src)
+{
+    return(0);
+}
+
+/* Load a SVG type image from an SDL datasource */
+SDL_Surface *IMG_LoadSizedSVG_RW(SDL_RWops *src, int width, int height)
+{
+    return(NULL);
+}
+
+#endif /* LOAD_SVG */
+
+/* Load a SVG type image from an SDL datasource */
+SDL_Surface *IMG_LoadSVG_RW(SDL_RWops *src)
+{
+    return IMG_LoadSizedSVG_RW(src, 0, 0);
+}
+