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// Copyright (c) 2010 LearnBoost <tj@learnboost.com>
#include "Image.h"
#include "InstanceData.h"
#include "bmp/BMPParser.h"
#include "Canvas.h"
#include <cerrno>
#include <cstdlib>
#include <cstring>
#include <node_buffer.h>
#include <sys/stat.h>
/* Cairo limit:
* https://lists.cairographics.org/archives/cairo/2010-December/021422.html
*/
static constexpr int canvas_max_side = (1 << 15) - 1;
#ifdef HAVE_GIF
typedef struct {
uint8_t *buf;
unsigned len;
unsigned pos;
} gif_data_t;
#endif
#ifdef HAVE_JPEG
#include <csetjmp>
struct canvas_jpeg_error_mgr: jpeg_error_mgr {
Image* image;
jmp_buf setjmp_buffer;
};
#endif
/*
* Read closure used by loadFromBuffer.
*/
typedef struct {
Napi::Env* env;
unsigned len;
uint8_t *buf;
} read_closure_t;
/*
* Initialize Image.
*/
void
Image::Initialize(Napi::Env& env, Napi::Object& exports) {
InstanceData *data = env.GetInstanceData<InstanceData>();
Napi::HandleScope scope(env);
Napi::Function ctor = DefineClass(env, "Image", {
InstanceAccessor<&Image::GetComplete>("complete", napi_default_jsproperty),
InstanceAccessor<&Image::GetWidth, &Image::SetWidth>("width", napi_default_jsproperty),
InstanceAccessor<&Image::GetHeight, &Image::SetHeight>("height", napi_default_jsproperty),
InstanceAccessor<&Image::GetNaturalWidth>("naturalWidth", napi_default_jsproperty),
InstanceAccessor<&Image::GetNaturalHeight>("naturalHeight", napi_default_jsproperty),
InstanceAccessor<&Image::GetDataMode, &Image::SetDataMode>("dataMode", napi_default_jsproperty),
StaticValue("MODE_IMAGE", Napi::Number::New(env, DATA_IMAGE), napi_default_jsproperty),
StaticValue("MODE_MIME", Napi::Number::New(env, DATA_MIME), napi_default_jsproperty)
});
// Used internally in lib/image.js
exports.Set("GetSource", Napi::Function::New(env, &GetSource));
exports.Set("SetSource", Napi::Function::New(env, &SetSource));
data->ImageCtor = Napi::Persistent(ctor);
exports.Set("Image", ctor);
}
/*
* Initialize a new Image.
*/
Image::Image(const Napi::CallbackInfo& info) : ObjectWrap<Image>(info), env(info.Env()) {
data_mode = DATA_IMAGE;
info.This().ToObject().Unwrap().Set("onload", env.Null());
info.This().ToObject().Unwrap().Set("onerror", env.Null());
filename = NULL;
_data = nullptr;
_data_len = 0;
_surface = NULL;
width = height = 0;
naturalWidth = naturalHeight = 0;
state = DEFAULT;
#ifdef HAVE_RSVG
_rsvg = NULL;
_is_svg = false;
_svg_last_width = _svg_last_height = 0;
#endif
}
/*
* Get complete boolean.
*/
Napi::Value
Image::GetComplete(const Napi::CallbackInfo& info) {
return Napi::Boolean::New(env, true);
}
/*
* Get dataMode.
*/
Napi::Value
Image::GetDataMode(const Napi::CallbackInfo& info) {
return Napi::Number::New(env, data_mode);
}
/*
* Set dataMode.
*/
void
Image::SetDataMode(const Napi::CallbackInfo& info, const Napi::Value& value) {
if (value.IsNumber()) {
int mode = value.As<Napi::Number>().Uint32Value();
data_mode = (data_mode_t) mode;
}
}
/*
* Get natural width
*/
Napi::Value
Image::GetNaturalWidth(const Napi::CallbackInfo& info) {
return Napi::Number::New(env, naturalWidth);
}
/*
* Get width.
*/
Napi::Value
Image::GetWidth(const Napi::CallbackInfo& info) {
return Napi::Number::New(env, width);
}
/*
* Set width.
*/
void
Image::SetWidth(const Napi::CallbackInfo& info, const Napi::Value& value) {
if (value.IsNumber()) {
width = value.As<Napi::Number>().Uint32Value();
}
}
/*
* Get natural height
*/
Napi::Value
Image::GetNaturalHeight(const Napi::CallbackInfo& info) {
return Napi::Number::New(env, naturalHeight);
}
/*
* Get height.
*/
Napi::Value
Image::GetHeight(const Napi::CallbackInfo& info) {
return Napi::Number::New(env, height);
}
/*
* Set height.
*/
void
Image::SetHeight(const Napi::CallbackInfo& info, const Napi::Value& value) {
if (value.IsNumber()) {
height = value.As<Napi::Number>().Uint32Value();
}
}
/*
* Get src path.
*/
Napi::Value
Image::GetSource(const Napi::CallbackInfo& info){
Napi::Env env = info.Env();
Image *img = Image::Unwrap(info.This().As<Napi::Object>());
return Napi::String::New(env, img->filename ? img->filename : "");
}
/*
* Clean up assets and variables.
*/
void
Image::clearData() {
if (_surface) {
cairo_surface_destroy(_surface);
Napi::MemoryManagement::AdjustExternalMemory(env, -_data_len);
_data_len = 0;
_surface = NULL;
}
delete[] _data;
_data = nullptr;
free(filename);
filename = NULL;
#ifdef HAVE_RSVG
if (_rsvg != NULL) {
g_object_unref(_rsvg);
_rsvg = NULL;
}
#endif
width = height = 0;
naturalWidth = naturalHeight = 0;
state = DEFAULT;
}
/*
* Set src path.
*/
void
Image::SetSource(const Napi::CallbackInfo& info){
Napi::Env env = info.Env();
Napi::Object This = info.This().As<Napi::Object>();
Image *img = Image::Unwrap(This);
cairo_status_t status = CAIRO_STATUS_READ_ERROR;
Napi::Value value = info[0];
img->clearData();
// Clear errno in case some unrelated previous syscall failed
errno = 0;
// url string
if (value.IsString()) {
std::string src = value.As<Napi::String>().Utf8Value();
if (img->filename) free(img->filename);
img->filename = strdup(src.c_str());
status = img->load();
// Buffer
} else if (value.IsBuffer()) {
uint8_t *buf = value.As<Napi::Buffer<uint8_t>>().Data();
unsigned len = value.As<Napi::Buffer<uint8_t>>().Length();
status = img->loadFromBuffer(buf, len);
}
if (status) {
Napi::Value onerrorFn;
if (This.Get("onerror").UnwrapTo(&onerrorFn) && onerrorFn.IsFunction()) {
Napi::Error arg;
if (img->errorInfo.empty()) {
arg = Napi::Error::New(env, Napi::String::New(env, cairo_status_to_string(status)));
} else {
arg = img->errorInfo.toError(env);
}
onerrorFn.As<Napi::Function>().Call({ arg.Value() });
}
} else {
img->loaded();
Napi::Value onloadFn;
if (This.Get("onload").UnwrapTo(&onloadFn) && onloadFn.IsFunction()) {
onloadFn.As<Napi::Function>().Call({});
}
}
}
/*
* Load image data from `buf` by sniffing
* the bytes to determine format.
*/
cairo_status_t
Image::loadFromBuffer(uint8_t *buf, unsigned len) {
uint8_t data[4] = {0};
memcpy(data, buf, (len < 4 ? len : 4) * sizeof(uint8_t));
if (isPNG(data)) return loadPNGFromBuffer(buf);
if (isGIF(data)) {
#ifdef HAVE_GIF
return loadGIFFromBuffer(buf, len);
#else
this->errorInfo.set("node-canvas was built without GIF support");
return CAIRO_STATUS_READ_ERROR;
#endif
}
if (isJPEG(data)) {
#ifdef HAVE_JPEG
if (DATA_IMAGE == data_mode) return loadJPEGFromBuffer(buf, len);
if (DATA_MIME == data_mode) return decodeJPEGBufferIntoMimeSurface(buf, len);
if ((DATA_IMAGE | DATA_MIME) == data_mode) {
cairo_status_t status;
status = loadJPEGFromBuffer(buf, len);
if (status) return status;
return assignDataAsMime(buf, len, CAIRO_MIME_TYPE_JPEG);
}
#else // HAVE_JPEG
this->errorInfo.set("node-canvas was built without JPEG support");
return CAIRO_STATUS_READ_ERROR;
#endif
}
// confirm svg using first 1000 chars
// if a very long comment precedes the root <svg> tag, isSVG returns false
unsigned head_len = (len < 1000 ? len : 1000);
if (isSVG(buf, head_len)) {
#ifdef HAVE_RSVG
return loadSVGFromBuffer(buf, len);
#else
this->errorInfo.set("node-canvas was built without SVG support");
return CAIRO_STATUS_READ_ERROR;
#endif
}
if (isBMP(buf, len))
return loadBMPFromBuffer(buf, len);
this->errorInfo.set("Unsupported image type");
return CAIRO_STATUS_READ_ERROR;
}
/*
* Load PNG data from `buf`.
*/
cairo_status_t
Image::loadPNGFromBuffer(uint8_t *buf) {
read_closure_t closure;
closure.len = 0;
closure.buf = buf;
closure.env = &env;
_surface = cairo_image_surface_create_from_png_stream(readPNG, &closure);
cairo_status_t status = cairo_surface_status(_surface);
if (status) return status;
return CAIRO_STATUS_SUCCESS;
}
/*
* Read PNG data.
*/
cairo_status_t
Image::readPNG(void *c, uint8_t *data, unsigned int len) {
read_closure_t *closure = (read_closure_t *) c;
memcpy(data, closure->buf + closure->len, len);
closure->len += len;
return CAIRO_STATUS_SUCCESS;
}
/*
* Destroy image and associated surface.
*/
Image::~Image() {
clearData();
}
/*
* Initiate image loading.
*/
cairo_status_t
Image::load() {
if (LOADING != state) {
state = LOADING;
return loadSurface();
}
return CAIRO_STATUS_READ_ERROR;
}
/*
* Set state, assign dimensions.
*/
void
Image::loaded() {
Napi::HandleScope scope(env);
state = COMPLETE;
width = naturalWidth = cairo_image_surface_get_width(_surface);
height = naturalHeight = cairo_image_surface_get_height(_surface);
_data_len = naturalHeight * cairo_image_surface_get_stride(_surface);
Napi::MemoryManagement::AdjustExternalMemory(env, _data_len);
}
/*
* Returns this image's surface.
*/
cairo_surface_t *Image::surface() {
#ifdef HAVE_RSVG
if (_is_svg && (_svg_last_width != width || _svg_last_height != height)) {
if (_surface != NULL) {
cairo_surface_destroy(_surface);
_surface = NULL;
}
cairo_status_t status = renderSVGToSurface();
if (status != CAIRO_STATUS_SUCCESS) {
g_object_unref(_rsvg);
Napi::Error::New(env, cairo_status_to_string(status)).ThrowAsJavaScriptException();
return NULL;
}
}
#endif
return _surface;
}
/*
* Load cairo surface from the image src.
*
* TODO: support more formats
* TODO: use node IO or at least thread pool
*/
cairo_status_t
Image::loadSurface() {
FILE *stream = fopen(filename, "rb");
if (!stream) {
this->errorInfo.set(NULL, "fopen", errno, filename);
return CAIRO_STATUS_READ_ERROR;
}
uint8_t buf[5];
if (1 != fread(&buf, 5, 1, stream)) {
fclose(stream);
return CAIRO_STATUS_READ_ERROR;
}
rewind(stream);
// png
if (isPNG(buf)) {
fclose(stream);
return loadPNG();
}
if (isGIF(buf)) {
#ifdef HAVE_GIF
return loadGIF(stream);
#else
this->errorInfo.set("node-canvas was built without GIF support");
return CAIRO_STATUS_READ_ERROR;
#endif
}
if (isJPEG(buf)) {
#ifdef HAVE_JPEG
return loadJPEG(stream);
#else
this->errorInfo.set("node-canvas was built without JPEG support");
return CAIRO_STATUS_READ_ERROR;
#endif
}
// confirm svg using first 1000 chars
// if a very long comment precedes the root <svg> tag, isSVG returns false
uint8_t head[1000] = {0};
fseek(stream, 0 , SEEK_END);
long len = ftell(stream);
unsigned head_len = (len < 1000 ? len : 1000);
unsigned head_size = head_len * sizeof(uint8_t);
rewind(stream);
if (head_size != fread(&head, 1, head_size, stream)) {
fclose(stream);
return CAIRO_STATUS_READ_ERROR;
}
rewind(stream);
if (isSVG(head, head_len)) {
#ifdef HAVE_RSVG
return loadSVG(stream);
#else
this->errorInfo.set("node-canvas was built without SVG support");
return CAIRO_STATUS_READ_ERROR;
#endif
}
if (isBMP(buf, 2))
return loadBMP(stream);
fclose(stream);
this->errorInfo.set("Unsupported image type");
return CAIRO_STATUS_READ_ERROR;
}
/*
* Load PNG.
*/
cairo_status_t
Image::loadPNG() {
_surface = cairo_image_surface_create_from_png(filename);
return cairo_surface_status(_surface);
}
// GIF support
#ifdef HAVE_GIF
/*
* Return the alpha color for `gif` at `frame`, or -1.
*/
int
get_gif_transparent_color(GifFileType *gif, int frame) {
ExtensionBlock *ext = gif->SavedImages[frame].ExtensionBlocks;
int len = gif->SavedImages[frame].ExtensionBlockCount;
for (int x = 0; x < len; ++x, ++ext) {
if ((ext->Function == GRAPHICS_EXT_FUNC_CODE) && (ext->Bytes[0] & 1)) {
return ext->Bytes[3] == 0 ? 0 : (uint8_t) ext->Bytes[3];
}
}
return -1;
}
/*
* Memory GIF reader callback.
*/
int
read_gif_from_memory(GifFileType *gif, GifByteType *buf, int len) {
gif_data_t *data = (gif_data_t *) gif->UserData;
if ((data->pos + len) > data->len) len = data->len - data->pos;
memcpy(buf, data->pos + data->buf, len);
data->pos += len;
return len;
}
/*
* Load GIF.
*/
cairo_status_t
Image::loadGIF(FILE *stream) {
struct stat s;
int fd = fileno(stream);
// stat
if (fstat(fd, &s) < 0) {
fclose(stream);
return CAIRO_STATUS_READ_ERROR;
}
uint8_t *buf = (uint8_t *) malloc(s.st_size);
if (!buf) {
fclose(stream);
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
size_t read = fread(buf, s.st_size, 1, stream);
fclose(stream);
cairo_status_t result = CAIRO_STATUS_READ_ERROR;
if (1 == read) result = loadGIFFromBuffer(buf, s.st_size);
free(buf);
return result;
}
/*
* Load give from `buf` and the given `len`.
*/
cairo_status_t
Image::loadGIFFromBuffer(uint8_t *buf, unsigned len) {
int i = 0;
GifFileType* gif;
gif_data_t gifd = { buf, len, 0 };
#if GIFLIB_MAJOR >= 5
int errorcode;
if ((gif = DGifOpen((void*) &gifd, read_gif_from_memory, &errorcode)) == NULL)
return CAIRO_STATUS_READ_ERROR;
#else
if ((gif = DGifOpen((void*) &gifd, read_gif_from_memory)) == NULL)
return CAIRO_STATUS_READ_ERROR;
#endif
if (GIF_OK != DGifSlurp(gif)) {
GIF_CLOSE_FILE(gif);
return CAIRO_STATUS_READ_ERROR;
}
if (gif->SWidth > canvas_max_side || gif->SHeight > canvas_max_side) {
GIF_CLOSE_FILE(gif);
return CAIRO_STATUS_INVALID_SIZE;
}
width = naturalWidth = gif->SWidth;
height = naturalHeight = gif->SHeight;
uint8_t *data = new uint8_t[naturalWidth * naturalHeight * 4];
if (!data) {
GIF_CLOSE_FILE(gif);
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
GifImageDesc *img = &gif->SavedImages[i].ImageDesc;
// local colormap takes precedence over global
ColorMapObject *colormap = img->ColorMap
? img->ColorMap
: gif->SColorMap;
if (colormap == nullptr) {
GIF_CLOSE_FILE(gif);
return CAIRO_STATUS_READ_ERROR;
}
int bgColor = 0;
int alphaColor = get_gif_transparent_color(gif, i);
if (gif->SColorMap) bgColor = (uint8_t) gif->SBackGroundColor;
else if(alphaColor >= 0) bgColor = alphaColor;
uint8_t *src_data = (uint8_t*) gif->SavedImages[i].RasterBits;
uint32_t *dst_data = (uint32_t*) data;
if (!gif->Image.Interlace) {
if (naturalWidth == img->Width && naturalHeight == img->Height) {
for (int y = 0; y < naturalHeight; ++y) {
for (int x = 0; x < naturalWidth; ++x) {
*dst_data = ((*src_data == alphaColor) ? 0 : 255) << 24
| colormap->Colors[*src_data].Red << 16
| colormap->Colors[*src_data].Green << 8
| colormap->Colors[*src_data].Blue;
dst_data++;
src_data++;
}
}
} else {
// Image does not take up whole "screen" so we need to fill-in the background
int bottom = img->Top + img->Height;
int right = img->Left + img->Width;
uint32_t bgPixel =
((bgColor == alphaColor) ? 0 : 255) << 24
| colormap->Colors[bgColor].Red << 16
| colormap->Colors[bgColor].Green << 8
| colormap->Colors[bgColor].Blue;
for (int y = 0; y < naturalHeight; ++y) {
for (int x = 0; x < naturalWidth; ++x) {
if (y < img->Top || y >= bottom || x < img->Left || x >= right) {
*dst_data = bgPixel;
dst_data++;
} else {
*dst_data = ((*src_data == alphaColor) ? 0 : 255) << 24
| colormap->Colors[*src_data].Red << 16
| colormap->Colors[*src_data].Green << 8
| colormap->Colors[*src_data].Blue;
dst_data++;
src_data++;
}
}
}
}
} else {
// Image is interlaced so that it streams nice over 14.4k and 28.8k modems :)
// We first load in 1/8 of the image, followed by another 1/8, followed by
// 1/4 and finally the remaining 1/2.
int ioffs[] = { 0, 4, 2, 1 };
int ijumps[] = { 8, 8, 4, 2 };
uint8_t *src_ptr = src_data;
uint32_t *dst_ptr;
for(int z = 0; z < 4; z++) {
for(int y = ioffs[z]; y < naturalHeight; y += ijumps[z]) {
dst_ptr = dst_data + naturalWidth * y;
for(int x = 0; x < naturalWidth; ++x) {
*dst_ptr = ((*src_ptr == alphaColor) ? 0 : 255) << 24
| (colormap->Colors[*src_ptr].Red) << 16
| (colormap->Colors[*src_ptr].Green) << 8
| (colormap->Colors[*src_ptr].Blue);
dst_ptr++;
src_ptr++;
}
}
}
}
GIF_CLOSE_FILE(gif);
// New image surface
_surface = cairo_image_surface_create_for_data(
data
, CAIRO_FORMAT_ARGB32
, naturalWidth
, naturalHeight
, cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, naturalWidth));
cairo_status_t status = cairo_surface_status(_surface);
if (status) {
delete[] data;
return status;
}
_data = data;
return CAIRO_STATUS_SUCCESS;
}
#endif /* HAVE_GIF */
// JPEG support
#ifdef HAVE_JPEG
// libjpeg 6.2 does not have jpeg_mem_src; define it ourselves here unless
// libjpeg 8 is installed.
#if JPEG_LIB_VERSION < 80 && !defined(MEM_SRCDST_SUPPORTED)
/* Read JPEG image from a memory segment */
static void
init_source(j_decompress_ptr cinfo) {}
static boolean
fill_input_buffer(j_decompress_ptr cinfo) {
ERREXIT(cinfo, JERR_INPUT_EMPTY);
return TRUE;
}
static void
skip_input_data(j_decompress_ptr cinfo, long num_bytes) {
struct jpeg_source_mgr* src = (struct jpeg_source_mgr*) cinfo->src;
if (num_bytes > 0) {
src->next_input_byte += (size_t) num_bytes;
src->bytes_in_buffer -= (size_t) num_bytes;
}
}
static void term_source (j_decompress_ptr cinfo) {}
static void jpeg_mem_src (j_decompress_ptr cinfo, void* buffer, long nbytes) {
struct jpeg_source_mgr* src;
if (cinfo->src == NULL) {
cinfo->src = (struct jpeg_source_mgr *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
sizeof(struct jpeg_source_mgr));
}
src = (struct jpeg_source_mgr*) cinfo->src;
src->init_source = init_source;
src->fill_input_buffer = fill_input_buffer;
src->skip_input_data = skip_input_data;
src->resync_to_restart = jpeg_resync_to_restart; /* use default method */
src->term_source = term_source;
src->bytes_in_buffer = nbytes;
src->next_input_byte = (JOCTET*)buffer;
}
#endif
class BufferReader : public Image::Reader {
public:
BufferReader(uint8_t* buf, unsigned len) : _buf(buf), _len(len), _idx(0) {}
bool hasBytes(unsigned n) const override { return (_idx + n - 1 < _len); }
uint8_t getNext() override {
return _buf[_idx++];
}
void skipBytes(unsigned n) override { _idx += n; }
private:
uint8_t* _buf; // we do not own this
unsigned _len;
unsigned _idx;
};
class StreamReader : public Image::Reader {
public:
StreamReader(FILE *stream) : _stream(stream), _len(0), _idx(0) {
fseek(_stream, 0, SEEK_END);
_len = ftell(_stream);
fseek(_stream, 0, SEEK_SET);
}
bool hasBytes(unsigned n) const override { return (_idx + n - 1 < _len); }
uint8_t getNext() override {
++_idx;
return getc(_stream);
}
void skipBytes(unsigned n) override {
_idx += n;
fseek(_stream, _idx, SEEK_SET);
}
private:
FILE* _stream;
unsigned _len;
unsigned _idx;
};
void Image::jpegToARGB(jpeg_decompress_struct* args, uint8_t* data, uint8_t* src, JPEGDecodeL decode) {
int stride = naturalWidth * 4;
for (int y = 0; y < naturalHeight; ++y) {
jpeg_read_scanlines(args, &src, 1);
uint32_t *row = (uint32_t*)(data + stride * y);
for (int x = 0; x < naturalWidth; ++x) {
int bx = args->output_components * x;
row[x] = decode(src + bx);
}
}
}
/*
* Takes an initialised jpeg_decompress_struct and decodes the
* data into _surface.
*/
cairo_status_t
Image::decodeJPEGIntoSurface(jpeg_decompress_struct *args, Orientation orientation) {
const int channels = 4;
cairo_status_t status = CAIRO_STATUS_SUCCESS;
uint8_t *data = new uint8_t[naturalWidth * naturalHeight * channels];
if (!data) {
jpeg_abort_decompress(args);
jpeg_destroy_decompress(args);
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
uint8_t *src = new uint8_t[naturalWidth * args->output_components];
if (!src) {
free(data);
jpeg_abort_decompress(args);
jpeg_destroy_decompress(args);
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
// These are the three main cases to handle. libjpeg converts YCCK to CMYK
// and YCbCr to RGB by default.
switch (args->out_color_space) {
case JCS_CMYK:
jpegToARGB(args, data, src, [](uint8_t const* src) {
uint16_t k = static_cast<uint16_t>(src[3]);
uint8_t r = k * src[0] / 255;
uint8_t g = k * src[1] / 255;
uint8_t b = k * src[2] / 255;
return 255 << 24 | r << 16 | g << 8 | b;
});
break;
case JCS_RGB:
jpegToARGB(args, data, src, [](uint8_t const* src) {
uint8_t r = src[0], g = src[1], b = src[2];
return 255 << 24 | r << 16 | g << 8 | b;
});
break;
case JCS_GRAYSCALE:
jpegToARGB(args, data, src, [](uint8_t const* src) {
uint8_t v = src[0];
return 255 << 24 | v << 16 | v << 8 | v;
});
break;
default:
this->errorInfo.set("Unsupported JPEG encoding");
status = CAIRO_STATUS_READ_ERROR;
break;
}
updateDimensionsForOrientation(orientation);
if (!status) {
_surface = cairo_image_surface_create_for_data(
data
, CAIRO_FORMAT_ARGB32
, naturalWidth
, naturalHeight
, cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, naturalWidth));
}
jpeg_finish_decompress(args);
jpeg_destroy_decompress(args);
status = cairo_surface_status(_surface);
rotatePixels(data, naturalWidth, naturalHeight, channels, orientation);
delete[] src;
if (status) {
delete[] data;
return status;
}
_data = data;
return CAIRO_STATUS_SUCCESS;
}
/*
* Callback to recover from jpeg errors
*/
static void canvas_jpeg_error_exit(j_common_ptr cinfo) {
canvas_jpeg_error_mgr *cjerr = static_cast<canvas_jpeg_error_mgr*>(cinfo->err);
cjerr->output_message(cinfo);
// Return control to the setjmp point
longjmp(cjerr->setjmp_buffer, 1);
}
// Capture libjpeg errors instead of writing stdout
static void canvas_jpeg_output_message(j_common_ptr cinfo) {
canvas_jpeg_error_mgr *cjerr = static_cast<canvas_jpeg_error_mgr*>(cinfo->err);
char buff[JMSG_LENGTH_MAX];
cjerr->format_message(cinfo, buff);
// (Only the last message will be returned to JS land.)
cjerr->image->errorInfo.set(buff);
}
/*
* Takes a jpeg data buffer and assigns it as mime data to a
* dummy surface
*/
cairo_status_t
Image::decodeJPEGBufferIntoMimeSurface(uint8_t *buf, unsigned len) {
// TODO: remove this duplicate logic
// JPEG setup
struct jpeg_decompress_struct args;
struct canvas_jpeg_error_mgr err;
err.image = this;
args.err = jpeg_std_error(&err);
args.err->error_exit = canvas_jpeg_error_exit;
args.err->output_message = canvas_jpeg_output_message;
// Establish the setjmp return context for canvas_jpeg_error_exit to use
if (setjmp(err.setjmp_buffer)) {
// If we get here, the JPEG code has signaled an error.
// We need to clean up the JPEG object, close the input file, and return.
jpeg_destroy_decompress(&args);
return CAIRO_STATUS_READ_ERROR;
}
jpeg_create_decompress(&args);
jpeg_mem_src(&args, buf, len);
jpeg_read_header(&args, 1);
jpeg_start_decompress(&args);
width = naturalWidth = args.output_width;
height = naturalHeight = args.output_height;
// Data alloc
// 8 pixels per byte using Alpha Channel format to reduce memory requirement.
int buf_size = naturalHeight * cairo_format_stride_for_width(CAIRO_FORMAT_A1, naturalWidth);
uint8_t *data = new uint8_t[buf_size];
if (!data) {
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
BufferReader reader(buf, len);
Orientation orientation = getExifOrientation(reader);
updateDimensionsForOrientation(orientation);
// New image surface
_surface = cairo_image_surface_create_for_data(
data
, CAIRO_FORMAT_A1
, naturalWidth
, naturalHeight
, cairo_format_stride_for_width(CAIRO_FORMAT_A1, naturalWidth));
// Cleanup
jpeg_abort_decompress(&args);
jpeg_destroy_decompress(&args);
cairo_status_t status = cairo_surface_status(_surface);
if (status) {
delete[] data;
return status;
}
rotatePixels(data, naturalWidth, naturalHeight, 1, orientation);
_data = data;
return assignDataAsMime(buf, len, CAIRO_MIME_TYPE_JPEG);
}
/*
* Helper function for disposing of a mime data closure.
*/
void
clearMimeData(void *closure) {
Napi::MemoryManagement::AdjustExternalMemory(
*static_cast<read_closure_t *>(closure)->env,
-static_cast<int>((static_cast<read_closure_t *>(closure)->len)));
free(static_cast<read_closure_t *>(closure)->buf);
free(closure);
}
/*
* Assign a given buffer as mime data against the surface.
* The provided buffer will be copied, and the copy will
* be automatically freed when the surface is destroyed.
*/
cairo_status_t
Image::assignDataAsMime(uint8_t *data, int len, const char *mime_type) {
uint8_t *mime_data = (uint8_t *) malloc(len);
if (!mime_data) {
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
read_closure_t *mime_closure = (read_closure_t *) malloc(sizeof(read_closure_t));
if (!mime_closure) {
free(mime_data);
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
memcpy(mime_data, data, len);
mime_closure->env = &env;
mime_closure->buf = mime_data;
mime_closure->len = len;
Napi::MemoryManagement::AdjustExternalMemory(env, len);
return cairo_surface_set_mime_data(_surface
, mime_type
, mime_data
, len
, clearMimeData
, mime_closure);
}
/*
* Load jpeg from buffer.
*/
cairo_status_t
Image::loadJPEGFromBuffer(uint8_t *buf, unsigned len) {
BufferReader reader(buf, len);
Orientation orientation = getExifOrientation(reader);
// TODO: remove this duplicate logic
// JPEG setup
struct jpeg_decompress_struct args;
struct canvas_jpeg_error_mgr err;
err.image = this;
args.err = jpeg_std_error(&err);
args.err->error_exit = canvas_jpeg_error_exit;
args.err->output_message = canvas_jpeg_output_message;
// Establish the setjmp return context for canvas_jpeg_error_exit to use
if (setjmp(err.setjmp_buffer)) {
// If we get here, the JPEG code has signaled an error.
// We need to clean up the JPEG object, close the input file, and return.
jpeg_destroy_decompress(&args);
return CAIRO_STATUS_READ_ERROR;
}
jpeg_create_decompress(&args);
jpeg_mem_src(&args, buf, len);
jpeg_read_header(&args, 1);
jpeg_start_decompress(&args);
width = naturalWidth = args.output_width;
height = naturalHeight = args.output_height;
return decodeJPEGIntoSurface(&args, orientation);
}
/*
* Load JPEG, convert RGB to ARGB.
*/
cairo_status_t
Image::loadJPEG(FILE *stream) {
cairo_status_t status;
#if defined(_MSC_VER)
if (false) { // Force using loadJPEGFromBuffer
#else
if (data_mode == DATA_IMAGE) { // Can lazily read in the JPEG.
#endif
Orientation orientation = NORMAL;
{
StreamReader reader(stream);
orientation = getExifOrientation(reader);
rewind(stream);
}
// JPEG setup
struct jpeg_decompress_struct args;
struct canvas_jpeg_error_mgr err;
err.image = this;
args.err = jpeg_std_error(&err);
args.err->error_exit = canvas_jpeg_error_exit;
args.err->output_message = canvas_jpeg_output_message;
// Establish the setjmp return context for canvas_jpeg_error_exit to use
if (setjmp(err.setjmp_buffer)) {
// If we get here, the JPEG code has signaled an error.
// We need to clean up the JPEG object, close the input file, and return.
jpeg_destroy_decompress(&args);
return CAIRO_STATUS_READ_ERROR;
}
jpeg_create_decompress(&args);
jpeg_stdio_src(&args, stream);
jpeg_read_header(&args, 1);
jpeg_start_decompress(&args);
if (args.output_width > canvas_max_side || args.output_height > canvas_max_side) {
jpeg_destroy_decompress(&args);
return CAIRO_STATUS_INVALID_SIZE;
}
width = naturalWidth = args.output_width;
height = naturalHeight = args.output_height;
status = decodeJPEGIntoSurface(&args, orientation);
fclose(stream);
} else { // We'll need the actual source jpeg data, so read fully.
uint8_t *buf;
unsigned len;
fseek(stream, 0, SEEK_END);
len = ftell(stream);
fseek(stream, 0, SEEK_SET);
buf = (uint8_t *) malloc(len);
if (!buf) {
this->errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
if (fread(buf, len, 1, stream) != 1) {
status = CAIRO_STATUS_READ_ERROR;
} else if ((DATA_IMAGE | DATA_MIME) == data_mode) {
status = loadJPEGFromBuffer(buf, len);
if (!status) status = assignDataAsMime(buf, len, CAIRO_MIME_TYPE_JPEG);
} else if (DATA_MIME == data_mode) {
status = decodeJPEGBufferIntoMimeSurface(buf, len);
}
#if defined(_MSC_VER)
else if (DATA_IMAGE == data_mode) {
status = loadJPEGFromBuffer(buf, len);
}
#endif
else {
status = CAIRO_STATUS_READ_ERROR;
}
fclose(stream);
free(buf);
}
return status;
}
/*
* Returns the Exif orientation if one exists, otherwise returns NORMAL
*/
Image::Orientation
Image::getExifOrientation(Reader& jpeg) {
static const char kJpegStartOfImage = (char)0xd8;
static const char kJpegStartOfFrameBaseline = (char)0xc0;
static const char kJpegStartOfFrameProgressive = (char)0xc2;
static const char kJpegHuffmanTable = (char)0xc4;
static const char kJpegQuantizationTable = (char)0xdb;
static const char kJpegRestartInterval = (char)0xdd;
static const char kJpegComment = (char)0xfe;
static const char kJpegStartOfScan = (char)0xda;
static const char kJpegApp0 = (char)0xe0;
static const char kJpegApp1 = (char)0xe1;
// Find the Exif tag (if it exists)
int exif_len = 0;
bool done = false;
while (!done && jpeg.hasBytes(1)) {
while (jpeg.hasBytes(1) && jpeg.getNext() != 0xff) {
// noop
}
if (jpeg.hasBytes(1)) {
char tag = jpeg.getNext();
switch (tag) {
case kJpegStartOfImage:
break; // beginning of file, no extra bytes
case kJpegRestartInterval:
jpeg.skipBytes(4);
break;
case kJpegStartOfFrameBaseline:
case kJpegStartOfFrameProgressive:
case kJpegHuffmanTable:
case kJpegQuantizationTable:
case kJpegComment:
case kJpegApp0:
case kJpegApp1: {
if (jpeg.hasBytes(2)) {
uint16_t tag_len = 0;
tag_len |= jpeg.getNext() << 8;
tag_len |= jpeg.getNext();
// The tag length includes the two bytes for the length
uint16_t tag_content_len = std::max(0, tag_len - 2);
if (tag != kJpegApp1 || !jpeg.hasBytes(tag_content_len)) {
jpeg.skipBytes(tag_content_len); // skip JPEG tags we ignore.
} else if (!jpeg.hasBytes(6)) {
jpeg.skipBytes(tag_content_len); // too short to have "Exif\0\0"
} else {
if (jpeg.getNext() == 'E' && jpeg.getNext() == 'x' &&
jpeg.getNext() == 'i' && jpeg.getNext() == 'f' &&
jpeg.getNext() == '\0' && jpeg.getNext() == '\0') {
exif_len = tag_content_len - 6;
done = true;
} else {
jpeg.skipBytes(tag_content_len); // too short to have "Exif\0\0"
}
}
} else {
done = true; // shouldn't happen: corrupt file or we have a bug
}
break;
}
case kJpegStartOfScan:
default:
done = true; // got to the image, apparently no exif tags here
break;
}
}
}
// Parse exif if it exists. If it does, we have already checked that jpeglen
// is longer than exifStart + exifLen, so we can safely index the data
if (exif_len > 0) {
// The first two bytes of TIFF header are "II" if little-endian ("Intel")
// and "MM" if big-endian ("Motorola")
const bool isLE = (jpeg.getNext() == 'I');
jpeg.skipBytes(3); // +1 for the other I/M, +2 for 0x002a
auto readUint16Little = [](Reader &jpeg) -> uint32_t {
uint16_t val = uint16_t(jpeg.getNext());
val |= uint16_t(jpeg.getNext()) << 8;
return val;
};
auto readUint32Little = [](Reader &jpeg) -> uint32_t {
uint32_t val = uint32_t(jpeg.getNext());
val |= uint32_t(jpeg.getNext()) << 8;
val |= uint32_t(jpeg.getNext()) << 16;
val |= uint32_t(jpeg.getNext()) << 24;
return val;
};
auto readUint16Big = [](Reader &jpeg) -> uint32_t {
uint16_t val = uint16_t(jpeg.getNext()) << 8;
val |= uint16_t(jpeg.getNext());
return val;
};
auto readUint32Big = [](Reader &jpeg) -> uint32_t {
uint32_t val = uint32_t(jpeg.getNext()) << 24;
val |= uint32_t(jpeg.getNext()) << 16;
val |= uint32_t(jpeg.getNext()) << 8;
val |= uint32_t(jpeg.getNext());
return val;
};
// The first two bytes of TIFF header are "II" if little-endian ("Intel")
// and "MM" if big-endian ("Motorola")
auto readUint32 = [readUint32Little, readUint32Big, isLE](Reader &jpeg) -> uint32_t {
return isLE ? readUint32Little(jpeg) : readUint32Big(jpeg);
};
auto readUint16 = [readUint16Little, readUint16Big, isLE](Reader &jpeg) -> uint32_t {
return isLE ? readUint16Little(jpeg) : readUint16Big(jpeg);
};
// offset to the IFD0 (offset from beginning of TIFF header, II/MM,
// which is 8 bytes before where we are after reading the uint32)
jpeg.skipBytes(readUint32(jpeg) - 8);
// Read the IFD0 ("Image File Directory 0")
// | NN | n entries in directory (2 bytes)
// | TT | tt | nnnn | vvvv | entry: tag (2b), data type (2b),
// n components (4b), value/offset (4b)
if (jpeg.hasBytes(2)) {
uint16_t nEntries = readUint16(jpeg);
for (uint16_t i = 0; i < nEntries && jpeg.hasBytes(2); ++i) {
uint16_t tag = readUint16(jpeg);
// The entry is 12 bytes. We already read the 2 bytes for the tag.
jpeg.skipBytes(6); // skip 2 for the data type, skip 4 n components.
if (tag == 0x112) {
switch (readUint16(jpeg)) { // orientation tag is always one uint16
case 1: return NORMAL;
case 2: return MIRROR_HORIZ;
case 3: return ROTATE_180;
case 4: return MIRROR_VERT;
case 5: return MIRROR_HORIZ_AND_ROTATE_270_CW;
case 6: return ROTATE_90_CW;
case 7: return MIRROR_HORIZ_AND_ROTATE_90_CW;
case 8: return ROTATE_270_CW;
default: return NORMAL;
}
} else {
jpeg.skipBytes(4); // skip the four bytes for the value
}
}
}
}
return NORMAL;
}
/*
* Updates the dimensions of the bitmap according to the orientation
*/
void Image::updateDimensionsForOrientation(Orientation orientation) {
switch (orientation) {
case ROTATE_90_CW:
case ROTATE_270_CW:
case MIRROR_HORIZ_AND_ROTATE_90_CW:
case MIRROR_HORIZ_AND_ROTATE_270_CW: {
int tmp = naturalWidth;
naturalWidth = naturalHeight;
naturalHeight = tmp;
tmp = width;
width = height;
height = tmp;
break;
}
case NORMAL:
case MIRROR_HORIZ:
case MIRROR_VERT:
case ROTATE_180:
default: {
break;
}
}
}
/*
* Rotates the pixels to the correct orientation.
*/
void
Image::rotatePixels(uint8_t* pixels, int width, int height, int channels,
Orientation orientation) {
auto swapPixel = [channels](uint8_t* pixels, int src_idx, int dst_idx) {
uint8_t tmp;
for (int i = 0; i < channels; ++i) {
tmp = pixels[src_idx + i];
pixels[src_idx + i] = pixels[dst_idx + i];
pixels[dst_idx + i] = tmp;
}
};
auto mirrorHoriz = [swapPixel](uint8_t* pixels, int width, int height, int channels) {
int midX = width / 2; // ok to truncate if odd, since we don't swap a center pixel
for (int y = 0; y < height; ++y) {
for (int x = 0; x < midX; ++x) {
int orig_idx = (y * width + x) * channels;
int new_idx = (y * width + width - 1 - x) * channels;
swapPixel(pixels, orig_idx, new_idx);
}
}
};
auto mirrorVert = [swapPixel](uint8_t* pixels, int width, int height, int channels) {
int midY = height / 2; // ok to truncate if odd, since we don't swap a center pixel
for (int y = 0; y < midY; ++y) {
for (int x = 0; x < width; ++x) {
int orig_idx = (y * width + x) * channels;
int new_idx = ((height - y - 1) * width + x) * channels;
swapPixel(pixels, orig_idx, new_idx);
}
}
};
auto rotate90 = [](uint8_t* pixels, int width, int height, int channels) {
const int n_bytes = width * height * channels;
uint8_t *unrotated = new uint8_t[n_bytes];
if (!unrotated) {
return;
}
std::memcpy(unrotated, pixels, n_bytes);
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width ; ++x) {
int orig_idx = (y * width + x) * channels;
int new_idx = (x * height + height - 1 - y) * channels;
std::memcpy(pixels + new_idx, unrotated + orig_idx, channels);
}
}
};
auto rotate270 = [](uint8_t* pixels, int width, int height, int channels) {
const int n_bytes = width * height * channels;
uint8_t *unrotated = new uint8_t[n_bytes];
if (!unrotated) {
return;
}
std::memcpy(unrotated, pixels, n_bytes);
for (int y = 0; y < height; ++y) {
for (int x = 0; x < width ; ++x) {
int orig_idx = (y * width + x) * channels;
int new_idx = ((width - 1 - x) * height + y) * channels;
std::memcpy(pixels + new_idx, unrotated + orig_idx, channels);
}
}
};
switch (orientation) {
case MIRROR_HORIZ:
mirrorHoriz(pixels, width, height, channels);
break;
case MIRROR_VERT:
mirrorVert(pixels, width, height, channels);
break;
case ROTATE_180:
mirrorHoriz(pixels, width, height, channels);
mirrorVert(pixels, width, height, channels);
break;
case ROTATE_90_CW:
rotate90(pixels, height, width, channels); // swap w/h because we need orig w/h
break;
case ROTATE_270_CW:
rotate270(pixels, height, width, channels); // swap w/h because we need orig w/h
break;
case MIRROR_HORIZ_AND_ROTATE_90_CW:
mirrorHoriz(pixels, height, width, channels); // swap w/h because we need orig w/h
rotate90(pixels, height, width, channels);
break;
case MIRROR_HORIZ_AND_ROTATE_270_CW:
mirrorHoriz(pixels, height, width, channels); // swap w/h because we need orig w/h
rotate270(pixels, height, width, channels);
break;
case NORMAL:
default:
break;
}
}
#endif /* HAVE_JPEG */
#ifdef HAVE_RSVG
/*
* Load SVG from buffer
*/
cairo_status_t
Image::loadSVGFromBuffer(uint8_t *buf, unsigned len) {
_is_svg = true;
if (NULL == (_rsvg = rsvg_handle_new_from_data(buf, len, nullptr))) {
return CAIRO_STATUS_READ_ERROR;
}
double d_width;
double d_height;
rsvg_handle_get_intrinsic_size_in_pixels(_rsvg, &d_width, &d_height);
width = naturalWidth = d_width;
height = naturalHeight = d_height;
if (width <= 0 || height <= 0) {
this->errorInfo.set("Width and height must be set on the svg element");
return CAIRO_STATUS_READ_ERROR;
}
return renderSVGToSurface();
}
/*
* Renders the Rsvg handle to this image's surface
*/
cairo_status_t
Image::renderSVGToSurface() {
cairo_status_t status;
_surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height);
status = cairo_surface_status(_surface);
if (status != CAIRO_STATUS_SUCCESS) {
g_object_unref(_rsvg);
return status;
}
cairo_t *cr = cairo_create(_surface);
status = cairo_status(cr);
if (status != CAIRO_STATUS_SUCCESS) {
g_object_unref(_rsvg);
return status;
}
RsvgRectangle viewport = {
0, // x
0, // y
static_cast<double>(width),
static_cast<double>(height)
};
gboolean render_ok = rsvg_handle_render_document(_rsvg, cr, &viewport, nullptr);
if (!render_ok) {
g_object_unref(_rsvg);
cairo_destroy(cr);
return CAIRO_STATUS_READ_ERROR; // or WRITE?
}
cairo_destroy(cr);
_svg_last_width = width;
_svg_last_height = height;
return status;
}
/*
* Load SVG
*/
cairo_status_t
Image::loadSVG(FILE *stream) {
_is_svg = true;
struct stat s;
int fd = fileno(stream);
// stat
if (fstat(fd, &s) < 0) {
fclose(stream);
return CAIRO_STATUS_READ_ERROR;
}
uint8_t *buf = (uint8_t *) malloc(s.st_size);
if (!buf) {
fclose(stream);
return CAIRO_STATUS_NO_MEMORY;
}
size_t read = fread(buf, s.st_size, 1, stream);
fclose(stream);
cairo_status_t result = CAIRO_STATUS_READ_ERROR;
if (1 == read) result = loadSVGFromBuffer(buf, s.st_size);
free(buf);
return result;
}
#endif /* HAVE_RSVG */
/*
* Load BMP from buffer.
*/
cairo_status_t Image::loadBMPFromBuffer(uint8_t *buf, unsigned len){
BMPParser::Parser parser;
// Reversed ARGB32 with pre-multiplied alpha
uint8_t pixFmt[5] = {2, 1, 0, 3, 1};
parser.parse(buf, len, pixFmt);
if (parser.getStatus() != BMPParser::Status::OK) {
errorInfo.reset();
errorInfo.message = parser.getErrMsg();
return CAIRO_STATUS_READ_ERROR;
}
width = naturalWidth = parser.getWidth();
height = naturalHeight = parser.getHeight();
uint8_t *data = parser.getImgd();
_surface = cairo_image_surface_create_for_data(
data,
CAIRO_FORMAT_ARGB32,
width,
height,
cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, width)
);
// No need to delete the data
cairo_status_t status = cairo_surface_status(_surface);
if (status) return status;
_data = data;
parser.clearImgd();
return CAIRO_STATUS_SUCCESS;
}
/*
* Load BMP.
*/
cairo_status_t Image::loadBMP(FILE *stream){
struct stat s;
int fd = fileno(stream);
// Stat
if (fstat(fd, &s) < 0) {
fclose(stream);
return CAIRO_STATUS_READ_ERROR;
}
uint8_t *buf = new uint8_t[s.st_size];
if (!buf) {
fclose(stream);
errorInfo.set(NULL, "malloc", errno);
return CAIRO_STATUS_NO_MEMORY;
}
size_t read = fread(buf, s.st_size, 1, stream);
fclose(stream);
cairo_status_t result = CAIRO_STATUS_READ_ERROR;
if (read == 1) result = loadBMPFromBuffer(buf, s.st_size);
delete[] buf;
return result;
}
/*
* Return UNKNOWN, SVG, GIF, JPEG, or PNG based on the filename.
*/
Image::type
Image::extension(const char *filename) {
size_t len = strlen(filename);
filename += len;
if (len >= 5 && 0 == strcmp(".jpeg", filename - 5)) return Image::JPEG;
if (len >= 4 && 0 == strcmp(".gif", filename - 4)) return Image::GIF;
if (len >= 4 && 0 == strcmp(".jpg", filename - 4)) return Image::JPEG;
if (len >= 4 && 0 == strcmp(".png", filename - 4)) return Image::PNG;
if (len >= 4 && 0 == strcmp(".svg", filename - 4)) return Image::SVG;
return Image::UNKNOWN;
}
/*
* Sniff bytes 0..1 for JPEG's magic number ff d8.
*/
int
Image::isJPEG(uint8_t *data) {
return 0xff == data[0] && 0xd8 == data[1];
}
/*
* Sniff bytes 0..2 for "GIF".
*/
int
Image::isGIF(uint8_t *data) {
return 'G' == data[0] && 'I' == data[1] && 'F' == data[2];
}
/*
* Sniff bytes 1..3 for "PNG".
*/
int
Image::isPNG(uint8_t *data) {
return 'P' == data[1] && 'N' == data[2] && 'G' == data[3];
}
/*
* Skip "<?" and "<!" tags to test if root tag starts "<svg"
*/
int
Image::isSVG(uint8_t *data, unsigned len) {
for (unsigned i = 3; i < len; i++) {
if ('<' == data[i-3]) {
switch (data[i-2]) {
case '?':
case '!':
break;
case 's':
return ('v' == data[i-1] && 'g' == data[i]);
default:
return false;
}
}
}
return false;
}
/*
* Check for valid BMP signatures
*/
int Image::isBMP(uint8_t *data, unsigned len) {
if(len < 2) return false;
std::string sig = std::string(1, (char)data[0]) + (char)data[1];
return sig == "BM" ||
sig == "BA" ||
sig == "CI" ||
sig == "CP" ||
sig == "IC" ||
sig == "PT";
}