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Add method for fast access to image metadata #32
This commit is contained in:
Lovell Fuller
parent
5fe945fca8
commit
f2f3eb76e1
15
README.md
15
README.md
@ -169,6 +169,21 @@ JPEG, PNG or WebP format image data can be streamed into the object when `input`
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JPEG, PNG or WebP format image data can be streamed out from this object.
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#### metadata([callback])
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Fast access to image metadata without decoding any compressed image data.
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`callback`, if present, gets the arguments `(err, metadata)` where `metadata` has the attributes:
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* `format`: Name of decoder to be used to decompress image data e.g. `jpeg`, `png`, `webp` (for file-based input additionally `tiff` and `magick`)
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* `width`: Number of pixels wide
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* `height`: Number of pixels high
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* `space`: Name of colour space interpretation e.g. `srgb`, `rgb`, `scrgb`, `cmyk`, `lab`, `xyz`, `b-w` [...](https://github.com/jcupitt/libvips/blob/master/libvips/iofuncs/enumtypes.c#L502)
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* `channels`: Number of bands e.g. `3` for sRGB, `4` for CMYK
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* `orientation`: Number value of the EXIF Orientation header, if present
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A Promises/A+ promise is returned when `callback` is not provided.
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#### sequentialRead()
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An advanced setting that switches the libvips access method to `VIPS_ACCESS_SEQUENTIAL`. This will reduce memory usage and can improve performance on some systems.
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42
index.js
42
index.js
@ -347,6 +347,48 @@ Sharp.prototype._sharp = function(callback) {
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}
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};
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/*
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Reads the image header and returns metadata
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Supports callback, stream and promise variants
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*/
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Sharp.prototype.metadata = function(callback) {
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var that = this;
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if (typeof callback === 'function') {
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if (this.options.streamIn) {
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this.on('finish', function() {
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sharp.metadata(that.options, callback);
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});
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} else {
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sharp.metadata(this.options, callback);
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}
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return this;
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} else {
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if (this.options.streamIn) {
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return new Promise(function(resolve, reject) {
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that.on('finish', function() {
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sharp.metadata(that.options, function(err, data) {
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if (err) {
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reject(err);
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} else {
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resolve(data);
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}
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});
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});
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});
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} else {
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return new Promise(function(resolve, reject) {
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sharp.metadata(that.options, function(err, data) {
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if (err) {
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reject(err);
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} else {
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resolve(data);
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}
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});
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});
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}
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}
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};
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/*
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Get and set cache memory and item limits
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*/
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260
src/sharp.cc
260
src/sharp.cc
@ -46,6 +46,7 @@ struct resize_baton {
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};
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typedef enum {
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UNKNOWN,
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JPEG,
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PNG,
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WEBP,
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@ -153,69 +154,223 @@ sharp_calc_crop(int const inWidth, int const inHeight, int const outWidth, int c
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return std::make_tuple(left, top);
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}
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class ResizeWorker : public NanAsyncWorker {
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public:
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ResizeWorker(NanCallback *callback, resize_baton *baton)
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: NanAsyncWorker(callback), baton(baton) {}
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~ResizeWorker() {}
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/*
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Initialise a VipsImage from a buffer. Supports JPEG, PNG and WebP.
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Returns the ImageType detected, if any.
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*/
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static ImageType
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sharp_init_image_from_buffer(VipsImage **image, void *buffer, size_t const length, VipsAccess const access) {
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ImageType imageType = UNKNOWN;
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if (memcmp(MARKER_JPEG, buffer, 2) == 0) {
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if (!vips_jpegload_buffer(buffer, length, image, "access", access, NULL)) {
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imageType = JPEG;
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}
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} else if(memcmp(MARKER_PNG, buffer, 2) == 0) {
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if (!vips_pngload_buffer(buffer, length, image, "access", access, NULL)) {
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imageType = PNG;
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}
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} else if(memcmp(MARKER_WEBP, buffer, 2) == 0) {
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if (!vips_webpload_buffer(buffer, length, image, "access", access, NULL)) {
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imageType = WEBP;
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}
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}
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return imageType;
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}
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void Execute () {
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/*
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Initialise a VipsImage from a file.
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Returns the ImageType detected, if any.
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*/
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static ImageType
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sharp_init_image_from_file(VipsImage **image, char const *file, VipsAccess const access) {
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ImageType imageType = UNKNOWN;
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if (vips_foreign_is_a("jpegload", file)) {
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if (!vips_jpegload(file, image, "access", access, NULL)) {
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imageType = JPEG;
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}
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} else if (vips_foreign_is_a("pngload", file)) {
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if (!vips_pngload(file, image, "access", access, NULL)) {
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imageType = PNG;
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}
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} else if (vips_foreign_is_a("webpload", file)) {
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if (!vips_webpload(file, image, "access", access, NULL)) {
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imageType = WEBP;
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}
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} else if (vips_foreign_is_a("tiffload", file)) {
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if (!vips_tiffload(file, image, "access", access, NULL)) {
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imageType = TIFF;
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}
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} else if(vips_foreign_is_a("magickload", file)) {
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if (!vips_magickload(file, image, "access", access, NULL)) {
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imageType = MAGICK;
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}
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}
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return imageType;
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}
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// Metadata
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struct metadata_baton {
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// Input
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std::string file_in;
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void* buffer_in;
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size_t buffer_in_len;
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// Output
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std::string format;
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int width;
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int height;
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std::string space;
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int channels;
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int orientation;
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std::string err;
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metadata_baton():
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buffer_in_len(0),
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orientation(0) {}
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};
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class MetadataWorker : public NanAsyncWorker {
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public:
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MetadataWorker(NanCallback *callback, metadata_baton *baton) : NanAsyncWorker(callback), baton(baton) {}
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~MetadataWorker() {}
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void Execute() {
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// Decrement queued task counter
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g_atomic_int_dec_and_test(&counter_queue);
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ImageType imageType = UNKNOWN;
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VipsImage *image = vips_image_new();
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if (baton->buffer_in_len > 1) {
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// From buffer
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imageType = sharp_init_image_from_buffer(&image, baton->buffer_in, baton->buffer_in_len, VIPS_ACCESS_RANDOM);
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if (imageType == UNKNOWN) {
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(baton->err).append("Input buffer contains unsupported image format");
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}
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} else {
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// From file
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imageType = sharp_init_image_from_file(&image, baton->file_in.c_str(), VIPS_ACCESS_RANDOM);
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if (imageType == UNKNOWN) {
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(baton->err).append("File is of an unsupported image format");
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}
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}
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if (imageType != UNKNOWN) {
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// Image type
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switch (imageType) {
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case JPEG: baton->format = "jpeg"; break;
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case PNG: baton->format = "png"; break;
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case WEBP: baton->format = "webp"; break;
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case TIFF: baton->format = "tiff"; break;
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case MAGICK: baton->format = "magick"; break;
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case UNKNOWN: default: baton->format = "";
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}
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// VipsImage attributes
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baton->width = image->Xsize;
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baton->height = image->Ysize;
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baton->space = vips_enum_nick(VIPS_TYPE_INTERPRETATION, image->Type);
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baton->channels = image->Bands;
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// EXIF Orientation
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const char *exif;
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if (!vips_image_get_string(image, "exif-ifd0-Orientation", &exif)) {
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baton->orientation = atoi(&exif[0]);
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}
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}
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// Clean up
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g_object_unref(image);
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vips_error_clear();
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vips_thread_shutdown();
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}
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void HandleOKCallback () {
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NanScope();
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Handle<Value> argv[2] = { NanNull(), NanNull() };
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if (!baton->err.empty()) {
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// Error
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argv[0] = NanNew<String>(baton->err.data(), baton->err.size());
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} else {
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// Metadata Object
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Local<Object> info = NanNew<Object>();
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info->Set(NanNew<String>("format"), NanNew<String>(baton->format));
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info->Set(NanNew<String>("width"), NanNew<Number>(baton->width));
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info->Set(NanNew<String>("height"), NanNew<Number>(baton->height));
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info->Set(NanNew<String>("space"), NanNew<String>(baton->space));
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info->Set(NanNew<String>("channels"), NanNew<Number>(baton->channels));
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if (baton->orientation > 0) {
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info->Set(NanNew<String>("orientation"), NanNew<Number>(baton->orientation));
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}
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argv[1] = info;
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}
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delete baton;
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// Return to JavaScript
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callback->Call(2, argv);
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}
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private:
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metadata_baton* baton;
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};
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/*
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metadata(options, callback)
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*/
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NAN_METHOD(metadata) {
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NanScope();
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// V8 objects are converted to non-V8 types held in the baton struct
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metadata_baton *baton = new metadata_baton;
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Local<Object> options = args[0]->ToObject();
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// Input filename
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baton->file_in = *String::Utf8Value(options->Get(NanNew<String>("fileIn"))->ToString());
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// Input Buffer object
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if (options->Get(NanNew<String>("bufferIn"))->IsObject()) {
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Local<Object> buffer = options->Get(NanNew<String>("bufferIn"))->ToObject();
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baton->buffer_in_len = Buffer::Length(buffer);
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baton->buffer_in = Buffer::Data(buffer);
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}
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// Join queue for worker thread
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NanCallback *callback = new NanCallback(args[1].As<v8::Function>());
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NanAsyncQueueWorker(new MetadataWorker(callback, baton));
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// Increment queued task counter
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g_atomic_int_inc(&counter_queue);
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NanReturnUndefined();
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}
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// Resize
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class ResizeWorker : public NanAsyncWorker {
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public:
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ResizeWorker(NanCallback *callback, resize_baton *baton) : NanAsyncWorker(callback), baton(baton) {}
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~ResizeWorker() {}
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void Execute() {
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// Decrement queued task counter
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g_atomic_int_dec_and_test(&counter_queue);
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// Increment processing task counter
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g_atomic_int_inc(&counter_process);
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// Input
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ImageType inputImageType = JPEG;
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ImageType inputImageType = UNKNOWN;
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VipsImage *in = vips_image_new();
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if (baton->buffer_in_len > 1) {
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if (memcmp(MARKER_JPEG, baton->buffer_in, 2) == 0) {
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if (vips_jpegload_buffer(baton->buffer_in, baton->buffer_in_len, &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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}
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} else if(memcmp(MARKER_PNG, baton->buffer_in, 2) == 0) {
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inputImageType = PNG;
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if (vips_pngload_buffer(baton->buffer_in, baton->buffer_in_len, &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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}
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} else if(memcmp(MARKER_WEBP, baton->buffer_in, 2) == 0) {
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inputImageType = WEBP;
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if (vips_webpload_buffer(baton->buffer_in, baton->buffer_in_len, &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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}
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} else {
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resize_error(baton, in);
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(baton->err).append("Unsupported input buffer");
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return;
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}
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} else if (vips_foreign_is_a("jpegload", baton->file_in.c_str())) {
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if (vips_jpegload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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}
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} else if (vips_foreign_is_a("pngload", baton->file_in.c_str())) {
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inputImageType = PNG;
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if (vips_pngload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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}
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} else if (vips_foreign_is_a("webpload", baton->file_in.c_str())) {
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inputImageType = WEBP;
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if (vips_webpload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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}
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} else if (vips_foreign_is_a("tiffload", baton->file_in.c_str())) {
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inputImageType = TIFF;
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if (vips_tiffload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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}
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} else if(vips_foreign_is_a("magickload", (baton->file_in).c_str())) {
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inputImageType = MAGICK;
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if (vips_magickload((baton->file_in).c_str(), &in, "access", baton->access_method, NULL)) {
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return resize_error(baton, in);
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// From buffer
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inputImageType = sharp_init_image_from_buffer(&in, baton->buffer_in, baton->buffer_in_len, baton->access_method);
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if (inputImageType == UNKNOWN) {
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(baton->err).append("Input buffer contains unsupported image format");
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}
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} else {
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resize_error(baton, in);
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(baton->err).append("Unsupported input file " + baton->file_in);
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return;
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// From file
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inputImageType = sharp_init_image_from_file(&in, baton->file_in.c_str(), baton->access_method);
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if (inputImageType == UNKNOWN) {
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(baton->err).append("File is of an unsupported image format");
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}
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}
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if (inputImageType == UNKNOWN) {
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return resize_error(baton, in);
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}
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// Get input image width and height
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@ -613,6 +768,7 @@ extern "C" void init(Handle<Object> target) {
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vips_cache_set_max_mem(100 * 1048576); // 100 MB
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vips_cache_set_max(500); // 500 operations
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// Methods available to JavaScript
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NODE_SET_METHOD(target, "metadata", metadata);
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NODE_SET_METHOD(target, "resize", resize);
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NODE_SET_METHOD(target, "cache", cache);
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NODE_SET_METHOD(target, "counters", counters);
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122
tests/unit.js
122
tests/unit.js
@ -18,6 +18,10 @@ var outputTiff = path.join(fixturesPath, "output.tiff");
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var inputJpgWithExif = path.join(fixturesPath, "Landscape_8.jpg"); // https://github.com/recurser/exif-orientation-examples/blob/master/Landscape_8.jpg
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var inputPng = path.join(fixturesPath, "50020484-00001.png"); // http://c.searspartsdirect.com/lis_png/PLDM/50020484-00001.png
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var inputWebp = path.join(fixturesPath, "4.webp"); // http://www.gstatic.com/webp/gallery/4.webp
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var inputGif = path.join(fixturesPath, "Crash_test.gif"); // http://upload.wikimedia.org/wikipedia/commons/e/e3/Crash_test.gif
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// Ensure cache limits can be set
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sharp.cache(0); // Disable
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sharp.cache(50, 500); // 50MB, 500 items
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@ -398,6 +402,124 @@ async.series([
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done();
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});
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},
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// Metadata - JPEG
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function(done) {
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sharp(inputJpg).metadata(function(err, metadata) {
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if (err) throw err;
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assert.strictEqual('jpeg', metadata.format);
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assert.strictEqual(2725, metadata.width);
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assert.strictEqual(2225, metadata.height);
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assert.strictEqual('srgb', metadata.space);
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assert.strictEqual(3, metadata.channels);
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assert.strictEqual('undefined', typeof metadata.orientation);
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done();
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});
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},
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// Metadata - JPEG with EXIF
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function(done) {
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sharp(inputJpgWithExif).metadata(function(err, metadata) {
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if (err) throw err;
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assert.strictEqual('jpeg', metadata.format);
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assert.strictEqual(450, metadata.width);
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assert.strictEqual(600, metadata.height);
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assert.strictEqual('srgb', metadata.space);
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assert.strictEqual(3, metadata.channels);
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assert.strictEqual(8, metadata.orientation);
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done();
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});
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},
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// Metadata - TIFF
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function(done) {
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sharp(inputTiff).metadata(function(err, metadata) {
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if (err) throw err;
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assert.strictEqual('tiff', metadata.format);
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assert.strictEqual(2464, metadata.width);
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assert.strictEqual(3248, metadata.height);
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assert.strictEqual('b-w', metadata.space);
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assert.strictEqual(1, metadata.channels);
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done();
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});
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},
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// Metadata - PNG
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function(done) {
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sharp(inputPng).metadata(function(err, metadata) {
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if (err) throw err;
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assert.strictEqual('png', metadata.format);
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assert.strictEqual(2809, metadata.width);
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assert.strictEqual(2074, metadata.height);
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assert.strictEqual('b-w', metadata.space);
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assert.strictEqual(1, metadata.channels);
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done();
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});
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},
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// Metadata - WebP
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function(done) {
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sharp(inputWebp).metadata(function(err, metadata) {
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if (err) throw err;
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assert.strictEqual('webp', metadata.format);
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assert.strictEqual(1024, metadata.width);
|
||||
assert.strictEqual(772, metadata.height);
|
||||
assert.strictEqual('srgb', metadata.space);
|
||||
assert.strictEqual(3, metadata.channels);
|
||||
done();
|
||||
});
|
||||
},
|
||||
// Metadata - GIF (via libmagick)
|
||||
function(done) {
|
||||
sharp(inputGif).metadata(function(err, metadata) {
|
||||
if (err) throw err;
|
||||
assert.strictEqual('magick', metadata.format);
|
||||
assert.strictEqual(800, metadata.width);
|
||||
assert.strictEqual(533, metadata.height);
|
||||
assert.strictEqual('srgb', metadata.space);
|
||||
assert.strictEqual(3, metadata.channels);
|
||||
done();
|
||||
});
|
||||
},
|
||||
// Metadata - Promise
|
||||
function(done) {
|
||||
sharp(inputJpg).metadata().then(function(metadata) {
|
||||
assert.strictEqual('jpeg', metadata.format);
|
||||
assert.strictEqual(2725, metadata.width);
|
||||
assert.strictEqual(2225, metadata.height);
|
||||
assert.strictEqual('srgb', metadata.space);
|
||||
assert.strictEqual(3, metadata.channels);
|
||||
done();
|
||||
});
|
||||
},
|
||||
// Metadata - Stream
|
||||
function(done) {
|
||||
var readable = fs.createReadStream(inputJpg);
|
||||
var pipeline = sharp().metadata(function(err, metadata) {
|
||||
if (err) throw err;
|
||||
assert.strictEqual('jpeg', metadata.format);
|
||||
assert.strictEqual(2725, metadata.width);
|
||||
assert.strictEqual(2225, metadata.height);
|
||||
assert.strictEqual('srgb', metadata.space);
|
||||
assert.strictEqual(3, metadata.channels);
|
||||
done();
|
||||
});
|
||||
readable.pipe(pipeline);
|
||||
},
|
||||
// Get metadata then resize to half width
|
||||
function(done) {
|
||||
var image = sharp(inputJpg);
|
||||
image.metadata(function(err, metadata) {
|
||||
if (err) throw err;
|
||||
assert.strictEqual('jpeg', metadata.format);
|
||||
assert.strictEqual(2725, metadata.width);
|
||||
assert.strictEqual(2225, metadata.height);
|
||||
assert.strictEqual('srgb', metadata.space);
|
||||
assert.strictEqual(3, metadata.channels);
|
||||
image.resize(metadata.width / 2).toBuffer(function(err, data, info) {
|
||||
if (err) throw err;
|
||||
assert.strictEqual(true, data.length > 0);
|
||||
assert.strictEqual(1362, info.width);
|
||||
assert.strictEqual(1112, info.height);
|
||||
done();
|
||||
})
|
||||
});
|
||||
},
|
||||
// Verify internal counters
|
||||
function(done) {
|
||||
var counters = sharp.counters();
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user