wxc397libtiff
Original Repository: https://gitlab.com/libtiff/libtiff
This repository contains libtiff, a third-party open-source software used for reading, writing, and manipulating TIFF (Tagged Image File Format) images. It provides a standardized set of interfaces to handle various complex features of the TIFF format, including support for multiple compression algorithms (e.g., LZW, Deflate, JPEG, etc.). In OpenHarmony, libtiff primarily serves as a foundational component of the media subsystem, providing decoding capabilities for TIFF image formats.
Directory Structure
archive/ Past archived files
build/ Build helper scripts
cmake/ CMake build configuration files
contrib/ Non-core code contributed by the community
doc/ Documentation
libtiff/ Source code and header files for the libtiff core library
port/ Platform compatibility interface code
test/ Test scripts and cases
tools/ Source code for binary tools like tiffcp, tiffdump, etc.
README.md README instructions
How to Use libtiff in OpenHarmony
System components in OpenHarmony need to reference the libtiff component in BUILD.gn to use it.
// BUILD.gn
external_deps += [ "libtiff:libtiff" ]
Decoding Steps Using libtiff
- Open the file
TIFF *TIFFOpen(const char *filename, const char *mode);
filename: The name of the file
mode: The file opening mode ("r" for reading)
- Read image metadata
int TIFFGetField(TIFF *tif, uint32_t tag, ...);
tif：TIFF file context
tag：The metadata tag to read
...：Variable argument list to receive the tag value
Example:
TIFFGetField(tif, TIFFTAG_IMAGEWIDTH, &imgWidth);
- Decode the image
int TIFFReadRGBAImage(TIFF *tif, uint32_t width, uint32_t height, uint32_t *raster, int stopOnError);
tif：TIFF file context
width：Image width
height：Image height
raster：Memory address of the first pixel data after decoding
stopOnError：Error handling strategy. If non-zero, stop immediately on error; if zero, attempt to skip errors and continue decoding.
Example:
uint32_t *raster = (uint32_t *)_TIFFmalloc(width * height * sizeof(uint32_t));
if (raster != NULL) {
if (TIFFReadRGBAImage(tif, width, height, raster, 0)) {
// 解码成功，处理 raster 中的数据
}
_TIFFfree(raster);
}
- Close the file
void TIFFClose(TIFF *tif)；
tif：TIFF file context
Feature Support
OpenHarmony currently integrates libtiff primarily for decoding and displaying TIFF images. Encoding (writing) of TIFF images and modification of metadata tags are not yet supported.
License
libtiff uses the LibTIFF License (a BSD-like license). See the LICENSE.md file in the root directory for details.