red()红色值

Name

red()红色值

Examples

color c = color(255, 204, 0); // Define color ‘c’

fill(c); // Use color variable ‘c’ as fill color

rect(15, 20, 35, 60); // Draw left rectangle

float redValue = red(c); // Get red in ‘c’

println(redValue); // Print “255.0”

fill(redValue, 0, 0); // Use ‘redValue’ in new fill

rect(50, 20, 35, 60); // Draw right rectangle

Description

Extracts the red value from a color, scaled to match current colorMode(). The value is always returned as a float, so be careful not to assign it to an int value.

The red() function is easy to use and understand, but it is slower than a technique called bit shifting. When working in colorMode(RGB, 255), you can acheive the same results as red() but with greater speed by using the right shift operator (>>) with a bit mask. For example, the following two lines of code are equivalent means of getting the red value of the color value c:

从颜色中提取红色值, 缩放以匹配当前 colorMode ()。该值始终作为浮点返回, 因此请注意不要将其赋给一个 int 值。

红色 () 函数易于使用和理解, 但它比称为位移位的技术慢。当工作在 colorMode (RGB, 255), 你可以获得相同的结果为红色 (), 但以更高的速度通过使用右移位操作符 (>>) 与位掩码。例如, 以下两行代码是获取颜色值 c 的红色值的等效方法:

float r1 = red(c); // Simpler, but slower to calculate

float r2 = c >> 16 & 0xFF; // Very fast to calculate

Syntax

red(rgb)

Parameters

Returns

float

Related

green()
blue()
alpha()
hue()
saturation()
brightness()
>> (right shift)