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/* Copyright 2012 The Chromium Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/**
* This file defines the <code>PPB_ImageData</code> struct for determining how
* a browser handles image data.
*/
[generate_thunk]
label Chrome {
M14 = 1.0
};
/**
* <code>PP_ImageDataFormat</code> is an enumeration of the different types of
* image data formats.
*
* The third part of each enumeration value describes the memory layout from
* the lowest address to the highest. For example, BGRA means the B component
* is stored in the lowest address, no matter what endianness the platform is
* using.
*
* The PREMUL suffix implies pre-multiplied alpha is used. In this mode, the
* red, green and blue color components of the pixel data supplied to an image
* data should be pre-multiplied by their alpha value. For example: starting
* with floating point color components, here is how to convert them to 8-bit
* premultiplied components for image data:
*
* ...components of a pixel, floats ranging from 0 to 1...
* <code>float red = 1.0f;</code>
* <code>float green = 0.50f;</code>
* <code>float blue = 0.0f;</code>
* <code>float alpha = 0.75f;</code>
* ...components for image data are 8-bit values ranging from 0 to 255...
* <code>uint8_t image_data_red_premul = (uint8_t)(red * alpha * 255.0f);
* </code>
* <code>uint8_t image_data_green_premul = (uint8_t)(green * alpha * 255.0f);
* </code>
* <code>uint8_t image_data_blue_premul = (uint8_t)(blue * alpha * 255.0f);
* </code>
* <code>uint8_t image_data_alpha_premul = (uint8_t)(alpha * 255.0f);</code>
*
* <strong>Note:</strong> The resulting pre-multiplied red, green and blue
* components should not be greater than the alpha value.
*/
[assert_size(4)]
enum PP_ImageDataFormat {
PP_IMAGEDATAFORMAT_BGRA_PREMUL,
PP_IMAGEDATAFORMAT_RGBA_PREMUL,
PP_IMAGEDATAFORMAT_LAST = PP_IMAGEDATAFORMAT_RGBA_PREMUL
};
/**
* The <code>PP_ImageDataDesc</code> structure represents a description of
* image data.
*/
[assert_size(16)]
struct PP_ImageDataDesc {
/**
* This value represents one of the image data types in the
* <code>PP_ImageDataFormat</code> enum.
*/
PP_ImageDataFormat format;
/** This value represents the size of the bitmap in pixels. */
PP_Size size;
/**
* This value represents the row width in bytes. This may be different than
* width * 4 since there may be padding at the end of the lines.
*/
int32_t stride;
};
/**
* The <code>PPB_ImageData</code> interface contains pointers to several
* functions for determining the browser's treatment of image data.
*/
interface PPB_ImageData {
/**
* GetNativeImageDataFormat() returns the browser's preferred format for
* image data. The browser uses this format internally for painting. Other
* formats may require internal conversions to paint or may have additional
* restrictions depending on the function.
*
* @return A <code>PP_ImageDataFormat</code> containing the preferred format.
*/
PP_ImageDataFormat GetNativeImageDataFormat();
/**
* IsImageDataFormatSupported() determines if the given image data format is
* supported by the browser. Note: <code>PP_IMAGEDATAFORMAT_BGRA_PREMUL</code>
* and <code>PP_IMAGEDATAFORMAT_RGBA_PREMUL</code> formats are always
* supported. Other image formats do not make this guarantee, and should be
* checked first with IsImageDataFormatSupported() before using.
*
* @param[in] format The image data format.
*
* @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
* image data format is supported by the browser.
*/
PP_Bool IsImageDataFormatSupported(
[in] PP_ImageDataFormat format);
/**
* Create() allocates an image data resource with the given format and size.
*
* For security reasons, if uninitialized, the bitmap will not contain random
* memory, but may contain data from a previous image produced by the same
* module if the bitmap was cached and re-used.
*
* @param[in] instance A <code>PP_Instance</code> identifying one instance
* of a module.
* @param[in] format The desired image data format.
* @param[in] size A pointer to a <code>PP_Size</code> containing the image
* size.
* @param[in] init_to_zero A <code>PP_Bool</code> to determine transparency
* at creation.
* Set the <code>init_to_zero</code> flag if you want the bitmap initialized
* to transparent during the creation process. If this flag is not set, the
* current contents of the bitmap will be undefined, and the module should
* be sure to set all the pixels.
*
* @return A <code>PP_Resource</code> with a nonzero ID on success or zero on
* failure. Failure means the instance, image size, or format was invalid.
*/
PP_Resource Create(
[in] PP_Instance instance,
[in] PP_ImageDataFormat format,
[in] PP_Size size,
[in] PP_Bool init_to_zero);
/**
* IsImageData() determines if a given resource is image data.
*
* @param[in] image_data A <code>PP_Resource</code> corresponding to image
* data.
*
* @return A <code>PP_Bool</code> with <code>PP_TRUE</code> if the given
* resource is an image data or <code>PP_FALSE</code> if the resource is
* invalid or some type other than image data.
*/
PP_Bool IsImageData(
[in] PP_Resource image_data);
/**
* Describe() computes the description of the
* image data.
*
* @param[in] image_data A <code>PP_Resource</code> corresponding to image
* data.
* @param[in,out] desc A pointer to a <code>PP_ImageDataDesc</code>
* containing the description.
*
* @return A <code>PP_Bool</code> with <code>PP_TRUE</code> on success or
* <code>PP_FALSE</code> if the resource is not an image data. On
* <code>PP_FALSE</code>, the <code>desc</code> structure will be filled
* with 0.
*/
[always_set_output_parameters]
PP_Bool Describe(
[in] PP_Resource image_data,
[out] PP_ImageDataDesc desc);
/**
* Map() maps an image data into the module address space.
*
* @param[in] image_data A <code>PP_Resource</code> corresponding to image
* data.
*
* @return A pointer to the beginning of the data.
*/
mem_t Map(
[in] PP_Resource image_data);
/**
* Unmap is a pointer to a function that unmaps an image data from the module
* address space.
*
* @param[in] image_data A <code>PP_Resource</code> corresponding to image
* data.
*/
void Unmap(
[in] PP_Resource image_data);
};
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