PHP imagepng() 函数中质量属性的标准值

发布于 2024-10-25 00:33:36 字数 234 浏览 1 评论 0原文

根据 PHP 的官方文档，imagepng() 函数具有以下签名：

bool imagepng ( resource $image [, string $filename [, int $quality [, int $filters ]]] )

我现在需要知道的是 $quality 的标准值是多少。我在文档中找不到它。

有没有一些资料来源可以解释它或任何了解它的人？

原文

According to PHP's official documentation the imagepng() function has the following signature:

bool imagepng ( resource $image [, string $filename [, int $quality [, int $filters ]]] )

What I need to know now is what the standard value of $quality is. I cannot find it anywhere in the documentation.

Is there some source that explains it or anyone who knows about it?

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中二柚 2024-11-01 00:33:36

来自 php 源代码（gd.h）：

/* 2.0.12: Compression level: 0-9 or -1, where 0 is NO COMPRESSION at all,
* 1 is FASTEST but produces larger files, 9 provides the best
* compression (smallest files) but takes a long time to compress, and
* -1 selects the default compiled into the zlib library.
*/

结论：
根据 Zlib 手册 (http://www.zlib.net/manual.html)，默认压缩级别设置为 6。

from php source (gd.h):

/* 2.0.12: Compression level: 0-9 or -1, where 0 is NO COMPRESSION at all,
* 1 is FASTEST but produces larger files, 9 provides the best
* compression (smallest files) but takes a long time to compress, and
* -1 selects the default compiled into the zlib library.
*/

Conclusion:
Based on the Zlib manual (http://www.zlib.net/manual.html) the default compression level is set to 6.

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要走就滚别墨迹 2024-11-01 00:33:36

来自：https://www.php.net/manual/en/function。图片png.php

压缩级别：从0（无
压缩）至 9。

默认值为 0

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瑕疵 2024-11-01 00:33:36

在php的源代码中，质量参数默认为0。但我不知道哪个值最适合图像处理。

static void _php_image_output(INTERNAL_FUNCTION_PARAMETERS, int image_type, char *tn, void (*func_p)())
{
    zval *imgind;
    char *file = NULL;
    long quality = 0, type = 0;

In php's source code quality parameter was defaulted to 0. But i havent idea for which value is optimal for image processing.

static void _php_image_output(INTERNAL_FUNCTION_PARAMETERS, int image_type, char *tn, void (*func_p)())
{
    zval *imgind;
    char *file = NULL;
    long quality = 0, type = 0;

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~没有更多了~