A zero-length Buffer is created if size is 0. Use buf. fill 0 to initialize such Buffer instances with zeroes. When using Buffer. allocUnsafe to allocate new Buffer instances, allocations under 4 KiB are sliced from a single pre-allocated Buffer. This allows applications to avoid the garbage collection overhead of creating many individually allocated Buffer instances. This approach improves both performance and memory usage by eliminating the need to track and clean up as many individual ArrayBuffer objects.

However, in the case where a developer may need to retain a small chunk of memory from a pool for an indeterminate amount of time, it may be appropriate to create an un-pooled Buffer instance using Buffer.

allocUnsafeSlow and then copying out the relevant bits. The string parameter can now be any TypedArray , DataView or ArrayBuffer. Returns the byte length of a string when encoded using encoding. This is not the same as String. length , which does not account for the encoding that is used to convert the string into bytes. For 'base64' , 'base64url' , and 'hex' , this function assumes valid input.

whitespace , the return value might be greater than the length of a Buffer created from the string. byteLength is returned. Compares buf1 to buf2 , typically for the purpose of sorting arrays of Buffer instances.

This is equivalent to calling buf1. compare buf2. Returns a new Buffer which is the result of concatenating all the Buffer instances in the list together.

If the list has no items, or if the totalLength is 0, then a new zero-length Buffer is returned. If totalLength is not provided, it is calculated from the Buffer instances in list by adding their lengths. If totalLength is provided, it is coerced to an unsigned integer. If the combined length of the Buffer s in list exceeds totalLength , the result is truncated to totalLength.

concat may also use the internal Buffer pool like Buffer. allocUnsafe does. Allocates a new Buffer using an array of bytes in the range 0 — Array entries outside that range will be truncated to fit into it. A TypeError will be thrown if array is not an Array or another type appropriate for Buffer. from variants. from array and Buffer. from string may also use the internal Buffer pool like Buffer. This creates a view of the ArrayBuffer without copying the underlying memory.

For example, when passed a reference to the. buffer property of a TypedArray instance, the newly created Buffer will share the same allocated memory as the TypedArray 's underlying ArrayBuffer. The optional byteOffset and length arguments specify a memory range within the arrayBuffer that will be shared by the Buffer. A TypeError will be thrown if arrayBuffer is not an ArrayBuffer or a SharedArrayBuffer or another type appropriate for Buffer.

It is important to remember that a backing ArrayBuffer can cover a range of memory that extends beyond the bounds of a TypedArray view. A new Buffer created using the buffer property of a TypedArray may extend beyond the range of the TypedArray :. A TypeError will be thrown if buffer is not a Buffer or another type appropriate for Buffer. For objects whose valueOf function returns a value not strictly equal to object , returns Buffer. from object. valueOf , offsetOrEncoding, length.

For objects that support Symbol. toPrimitive , returns Buffer. from object[Symbol. toPrimitive] 'string' , offsetOrEncoding. A TypeError will be thrown if object does not have the mentioned methods or is not of another type appropriate for Buffer. Creates a new Buffer containing string.

The encoding parameter identifies the character encoding to be used when converting string into bytes. A TypeError will be thrown if string is not a string or another type appropriate for Buffer.

Returns true if obj is a Buffer , false otherwise. Returns true if encoding is the name of a supported character encoding, or false otherwise. This is the size in bytes of pre-allocated internal Buffer instances used for pooling. This value may be modified. The index operator [index] can be used to get and set the octet at position index in buf. The values refer to individual bytes, so the legal value range is between 0x00 and 0xFF hex or 0 and decimal.

This operator is inherited from Uint8Array , so its behavior on out-of-bounds access is the same as Uint8Array.

In other words, buf[index] returns undefined when index is negative or greater or equal to buf. This ArrayBuffer is not guaranteed to correspond exactly to the original Buffer. See the notes on buf. byteOffset for details. When setting byteOffset in Buffer. from ArrayBuffer, byteOffset, length , or sometimes when allocating a Buffer smaller than Buffer.

poolSize , the buffer does not start from a zero offset on the underlying ArrayBuffer. This can cause problems when accessing the underlying ArrayBuffer directly using buf. buffer , as other parts of the ArrayBuffer may be unrelated to the Buffer object itself. A common issue when creating a TypedArray object that shares its memory with a Buffer is that in this case one needs to specify the byteOffset correctly:. Compares buf with target and returns a number indicating whether buf comes before, after, or is the same as target in sort order.

Comparison is based on the actual sequence of bytes in each Buffer. The optional targetStart , targetEnd , sourceStart , and sourceEnd arguments can be used to limit the comparison to specific ranges within target and buf respectively. Copies data from a region of buf to a region in target , even if the target memory region overlaps with buf. set performs the same operation, and is available for all TypedArrays, including Node. js Buffer s, although it takes different function arguments.

Creates and returns an iterator of [index, byte] pairs from the contents of buf. Returns true if both buf and otherBuffer have exactly the same bytes, false otherwise. Equivalent to buf. Fills buf with the specified value. If the offset and end are not given, the entire buf will be filled:. value is coerced to a uint32 value if it is not a string, Buffer , or integer. If the final write of a fill operation falls on a multi-byte character, then only the bytes of that character that fit into buf are written:.

If value contains invalid characters, it is truncated; if no valid fill data remains, an exception is thrown:. When encoding is being passed, the byteOffset parameter is no longer required. If value is not a string, number, or Buffer , this method will throw a TypeError. If value is a number, it will be coerced to a valid byte value, an integer between 0 and If byteOffset is not a number, it will be coerced to a number.

If the result of coercion is NaN or 0 , then the entire buffer will be searched. This behavior matches String. If value is an empty string or empty Buffer and byteOffset is less than buf. length , byteOffset will be returned. If value is empty and byteOffset is at least buf. length , buf. length will be returned. Creates and returns an iterator of buf keys indices. Identical to buf. indexOf , except the last occurrence of value is found rather than the first occurrence.

Any arguments that coerce to NaN , like {} or undefined , will search the whole buffer. If value is an empty string or empty Buffer , byteOffset will be returned. Reads a signed, big-endian bit integer from buf at the specified offset. Reads a signed, little-endian bit integer from buf at the specified offset. Reads an unsigned, big-endian bit integer from buf at the specified offset.

Reads an unsigned, little-endian bit integer from buf at the specified offset. Removed noAssert and no implicit coercion of the offset to uint32 anymore. Removed noAssert and no implicit coercion of the offset and byteLength to uint32 anymore. Reads byteLength number of bytes from buf at the specified offset and interprets the result as a big-endian, two's complement signed value supporting up to 48 bits of accuracy. Reads byteLength number of bytes from buf at the specified offset and interprets the result as a little-endian, two's complement signed value supporting up to 48 bits of accuracy.

Reads byteLength number of bytes from buf at the specified offset and interprets the result as an unsigned big-endian integer supporting up to 48 bits of accuracy. Reads byteLength number of bytes from buf at the specified offset and interprets the result as an unsigned, little-endian integer supporting up to 48 bits of accuracy. Returns a new Buffer that references the same memory as the original, but offset and cropped by the start and end indices. Specifying end greater than buf.

length will return the same result as that of end equal to buf. This method is inherited from TypedArray. Modifying the new Buffer slice will modify the memory in the original Buffer because the allocated memory of the two objects overlap. Specifying negative indexes causes the slice to be generated relative to the end of buf rather than the beginning. This method is not compatible with the Uint8Array. slice , which is a superclass of Buffer. To copy the slice, use Uint8Array.

Interprets buf as an array of unsigned bit integers and swaps the byte order in-place. length is not a multiple of 2. One convenient use of buf. swap16 is to perform a fast in-place conversion between UTF little-endian and UTF big-endian:. length is not a multiple of 4. Interprets buf as an array of bit numbers and swaps byte order in-place. length is not a multiple of 8.

Returns a JSON representation of buf. stringify implicitly calls this function when stringifying a Buffer instance. from accepts objects in the format returned from this method. In particular, Buffer. from buf. toJSON works like Buffer. Decodes buf to a string according to the specified character encoding in encoding. start and end may be passed to decode only a subset of buf. The maximum length of a string instance in UTF code units is available as buffer. Creates and returns an iterator for buf values bytes.

This function is called automatically when a Buffer is used in a for.. of statement. Writes string to buf at offset according to the character encoding in encoding. The length parameter is the number of bytes to write. If buf did not contain enough space to fit the entire string, only part of string will be written.

However, partially encoded characters will not be written. Writes value to buf at the specified offset as big-endian. Writes value to buf at the specified offset as little-endian.

The value must be a JavaScript number. Behavior is undefined when value is anything other than a JavaScript number. Writes value to buf at the specified offset. value must be a valid signed 8-bit integer.

Behavior is undefined when value is anything other than a signed 8-bit integer. The value must be a valid signed bit integer. Behavior is undefined when value is anything other than a signed bit integer. Writes byteLength bytes of value to buf at the specified offset as big-endian. Supports up to 48 bits of accuracy. Behavior is undefined when value is anything other than a signed integer. Writes byteLength bytes of value to buf at the specified offset as little-endian.

value must be a valid unsigned 8-bit integer. Behavior is undefined when value is anything other than an unsigned 8-bit integer. The value must be a valid unsigned bit integer. Behavior is undefined when value is anything other than an unsigned bit integer. Behavior is undefined when value is anything other than an unsigned integer. See Buffer. from arrayBuffer[, byteOffset[, length]]. alloc and Buffer. This variant of the constructor is equivalent to Buffer.

from string[, encoding]. A File provides information about files. While, the Buffer object is available as a global, there are additional Buffer -related APIs that are available only via the node:buffer module accessed using require 'node:buffer'.

Decodes a string of Baseencoded data into bytes, and encodes those bytes into a string using Latin-1 ISO This function is only provided for compatibility with legacy web platform APIs and should never be used in new code, because they use strings to represent binary data and predate the introduction of typed arrays in JavaScript. For code running using Node.

js APIs, converting between baseencoded strings and binary data should be performed using Buffer. from str, 'base64' and buf. toString 'base64'. Decodes a string into bytes using Latin-1 ISO , and encodes those bytes into a string using Base Returns the maximum number of bytes that will be returned when buf.

inspect is called. This can be overridden by user modules. See util. inspect for more details on buf. inspect behavior. An alias for buffer. Resolves a 'blob:nodedata Re-encodes the given Buffer or Uint8Array instance from one character encoding to another. Returns a new Buffer instance.

Throws if the fromEnc or toEnc specify invalid character encodings or if conversion from fromEnc to toEnc is not permitted. Encodings supported by buffer. transcode are: 'ascii' , 'utf8' , 'utf16le' , 'ucs2' , 'latin1' , and 'binary'.

The transcoding process will use substitution characters if a given byte sequence cannot be adequately represented in the target encoding. For instance:. in the transcoded Buffer. This was never a class in the sense that the constructor always returned a Buffer instance, rather than a SlowBuffer instance.

It reflects vTypedArray::kMaxLength under the hood. Represents the largest length that a string primitive can have, counted in UTF code units. In versions of Node. js prior to 6. Because the behavior of new Buffer is different depending on the type of the first argument, security and reliability issues can be inadvertently introduced into applications when argument validation or Buffer initialization is not performed. For example, if an attacker can cause an application to receive a number where a string is expected, the application may call new Buffer instead of new Buffer "" , leading it to allocate a byte buffer instead of allocating a 3 byte buffer with content "".

This is commonly possible using JSON API calls. Since JSON distinguishes between numeric and string types, it allows injection of numbers where a naively written application that does not validate its input sufficiently might expect to always receive a string. Before Node. Since Node. However, other attacks are still possible, such as causing very large buffers to be allocated by the server, leading to performance degradation or crashing on memory exhaustion.

To make the creation of Buffer instances more reliable and less error-prone, the various forms of the new Buffer constructor have been deprecated and replaced by separate Buffer. from , Buffer. alloc , and Buffer. allocUnsafe methods. Developers should migrate all existing uses of the new Buffer constructors to one of these new APIs. Buffer instances returned by Buffer. allocUnsafe and Buffer.

from array may be allocated off a shared internal memory pool if size is less than or equal to half Buffer. Instances returned by Buffer.

allocUnsafeSlow never use the shared internal memory pool. js can be started using the --zero-fill-buffers command-line option to cause all newly-allocated Buffer instances to be zero-filled upon creation by default. Without the option, buffers created with Buffer. allocUnsafeSlow , and new SlowBuffer size are not zero-filled. Use of this flag can have a measurable negative impact on performance.

Use the --zero-fill-buffers option only when necessary to enforce that newly allocated Buffer instances cannot contain old data that is potentially sensitive. When calling Buffer. allocUnsafeSlow , the segment of allocated memory is uninitialized it is not zeroed-out. NVIDIA Virtual GPU Customers. Beta, Older drivers and more. Download Drivers. NVIDIA Driver Downloads. The NVIDIA RTX Enterprise Production Branch driver is a rebrand of the Quadro Optimal Driver for Enterprise ODE.

It offers the same ISV certification, long life-cycle support, regular security updates, and access to the same functionality as prior Quadro ODE drivers and corresponding Studio Drivers i. Support duration for New Feature Branches is shorter than that for Production Branches. All NVIDIA drivers provide full features and application support for top games and creative applications. If you are a gamer who prioritizes day of launch support for the latest games, patches, and DLCs, choose Game Ready Drivers.

If you are a content creator who prioritizes stability and quality for creative workflows including video editing, animation, photography, graphic design, and livestreaming, choose Studio Drivers.

Production Branch Production Branch drivers provide ISV certification and optimal stability and performance for Unix customers. This driver is most commonly deployed at enterprises, providing support for the sustained bug fix and security updates commonly required.

New Feature Branch New Feature Branch drivers provide early adopters and bleeding edge developers access to the latest driver features before they are integrated into the Production Branches.

Select from the dropdown list below to identify the appropriate driver for your NVIDIA product. Driver Software HDMI Audio Driver. Standard DCH. Game Ready Driver GRD Studio Driver SD.

Below is list of command-line options recognized by the ImageMagick command-line tools. If you want a description of a particular option, click on the option name in the navigation bar above and you will go right to it. Unless otherwise noted, each option is recognized by the commands: convert and mogrify.

A Gaussian operator of the given radius and standard deviation sigma is used. If sigma is not given it defaults to 1. The sigma value is the important argument, and determines the actual amount of blurring that will take place. The radius is only used to determine the size of the array which holds the calculated Gaussian distribution.

It should be an integer. If not given, or set to zero, IM will calculate the largest possible radius that will provide meaningful results for the Gaussian distribution. See Image Geometry for complete details about the geometry argument. The -adaptive-resize option defaults to data-dependent triangulation. Use the -filter to choose a different resampling algorithm.

Offsets, if present in the geometry string, are ignored, and the -gravity option has no effect. This option is enabled by default. An attempt is made to save all images of an image sequence into the given output file. However, some formats, such as JPEG and PNG, do not support more than one image per file, and in that case ImageMagick is forced to write each image as a separate file. As such, if more than one image needs to be written, the filename given is modified by adding a -scene number before the suffix, in order to make distinct names for each image.

As an example, the command. will create a sequence of 17 images the two given plus 15 more created by -morph , named: my00morph. jpg, my01morph. jpg, my02morph. In summary, ImageMagick tries to write all images to one file, but will save to multiple files, if any of the following conditions exist Set the drawing transformation matrix for combined rotating and scaling.

This option sets a transformation matrix, for use by subsequent -draw or -transform options. The matrix entries are entered as comma-separated numeric values either in quotes or without spaces. Internally, the transformation matrix has 3x3 elements, but three of them are omitted from the input because they are constant. The new transformed coordinates x' , y' of a pixel at position x , y in the original image are calculated using the following matrix equation.

The size of the resulting image is that of the smallest rectangle that contains the transformed source image. The parameters t x and t y subsequently shift the image pixels so that those that are moved out of the image area are cut off. The transformation matrix complies with the left-handed pixel coordinate system: positive x and y directions are rightward and downward, resp.

If the translation coefficients t x and t y are omitted they default to 0,0. Therefore, four parameters suffice for rotation and scaling without translation. Scaling by the factors s x and s y in the x and y directions, respectively, is accomplished with the following. See -transform , and the -distort method ' Affineprojection for more information.

Translation by a displacement t x , t y is accomplished like so:. The cumulative effect of a sequence of -affine transformations can be accomplished by instead by a single -affine operation using the matrix equal to the product of the matrices of the individual transformations. An attempt is made to detect near-singular transformation matrices. If the matrix determinant has a sufficiently small absolute value it is rejected. Used to set a flag on an image indicating whether or not to use existing alpha channel data, to create an alpha channel, or to perform other operations on the alpha channel.

Choose the argument type from the list below. This is a convenience for annotating an image with text. For more precise control over text annotations, use -draw. The values Xdegrees and Ydegrees control the shears applied to the text, while t x and t y are offsets that give the location of the text relative any -gravity setting and defaults to the upper left corner of the image.

Using -annotate degrees or -annotate degrees x degrees produces an unsheared rotation of the text. The direction of the rotation is positive, which means a clockwise rotation if degrees is positive.

This conforms to the usual mathematical convention once it is realized that the positive y —direction is conventionally considered to be downward for images. The new transformed coordinates x' , y' of a pixel at position x , y in the image are calculated using the following matrix equation.

If t x and t y are omitted, they default to 0. This makes the bottom-left of the text becomes the upper-left corner of the image, which is probably undesirable. Adding a -gravity option in this case leads to nice results. Text is any UTF-8 encoded character sequence. If text is of the form ' mytext. txt', the text is read from the file mytext. Text in a file is taken literally; no embedded formatting characters are recognized.

By default, objects e. text, lines, polygons, etc. are antialiased when drawn. This will then reduce the number of colors added to an image to just the colors being directly drawn. That is, no mixed colors are added when drawing such objects.

This option creates a single longer image, by joining all the current images in sequence top-to-bottom. If they are not of the same width, narrower images are padded with the current -background color setting, and their position relative to each other can be controlled by the current -gravity setting. For more flexible options, including the ability to add space between images, use -smush.

Use this option to supply a password for decrypting a PDF that has been encrypted using Microsoft Crypto API MSC API. The encrypting using the MSC API is not supported. For a different encryption method, see -encipher and -decipher. This works well for real-life images with little or no extreme dark and light areas, but tend to fail for images with large amounts of bright sky or dark shadows. It also does not work well for diagrams or cartoon like images. It uses the -channel setting, including the ' sync ' flag for channel synchronization , to determine which color values is used and modified.

As the default -channel setting is ' RGB,sync ', channels are modified together by the same gamma value, preserving colors.

This is a 'perfect' image normalization operator. It finds the exact minimum and maximum color values in the image and then applies a -level operator to stretch the values to the full range of values.

On the other hand it is the right operator to use for color stretching gradient images being used to generate Color lookup tables, distortion maps, or other 'mathematically' defined images. The operator is very similar to the -normalize , -contrast-stretch , and -linear-stretch operators, but without 'histogram binning' or 'clipping' problems that these operators may have.

That is -auto-level is the perfect or ideal version these operators. It uses the -channel setting, including the special ' sync ' flag for channel synchronization , to determine which color values are used and modified. Adjusts an image so that its orientation is suitable for viewing i.

top-left orientation. This operator reads and resets the EXIF image profile setting 'Orientation' and then performs the appropriate 90 degree rotation on the image to orient the image, for correct viewing. This EXIF profile setting is usually set using a gravity sensor in digital camera, however photos taken directly downward or upward may not have an appropriate value.

Also images that have been orientation 'corrected' without reseting this setting, may be 'corrected' again resulting in a incorrect result. If the EXIF profile was previously stripped, the -auto-orient operator will do nothing.

The computed threshold is returned as the auto-threshold:verbose image property. This backdrop covers the entire workstation screen and is useful for hiding other X window activity while viewing the image. The color of the backdrop is specified as the background color. The color is specified using the format described under the -fill option.

The default background color if none is specified or found in the image is white. Repeat the entire command for the given number of iterations and report the user-time and elapsed time.

For instance, consider the following command and its output. Modify the benchmark with the -duration to run the benchmark for a fixed number of seconds and -concurrent to run the benchmark in parallel requires the OpenMP feature.

In this example, 5 iterations were completed at 2. This option shifts the output of -convolve so that positive and negative results are relative to the specified bias value. This is important for non-HDRI compilations of ImageMagick when dealing with convolutions that contain negative as well as positive values. This is especially the case with convolutions involving high pass filters or edge detection. Without an output bias, the negative values are clipped at zero.

See the discussion on HDRI implementations of ImageMagick on the page High Dynamic-Range Images. For more about HDRI go the ImageMagick Usage pages or this Wikipedia entry. A non-linear, edge-preserving, and noise-reducing smoothing filter for images. It replaces the intensity of each pixel with a weighted average of intensity values from nearby pixels. This weight is based on a Gaussian distribution.

爆款少儿青少年scratch编程第11课：钓鱼大作战 可以直接运行。A53课程制作 爆款爆款少儿青少年scratch编程是包括教程制作完整课程，里面包括教学步骤，教学视频，教学素材，教学课件pdf，教学课件word，课程源码。课程内容大致如下所示：资源:. And work effortlessly with people who use Microsoft Excel. Print a list of supported arguments for various options or settings. Resolves a 'blob:nodedata The default unit of measure is in dots per inch DPI.

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