blue()蓝色值

Name

blue()蓝色值

Examples

color c = color(175, 100, 220); // Define color ‘c’

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

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

float blueValue = blue(c); // Get blue in ‘c’

println(blueValue); // Prints “220.0”

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

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

Description

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

从颜色中提取蓝色值, 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。

蓝色 () 函数易于使用和理解, 但它比称为比特掩蔽的技术慢。在 colorMode (RGB、255) 中工作时, 可以通过使用位掩码移除其他颜色组件来获得与蓝色 () 相同的结果, 但速度更大。例如, 以下两行代码是获取颜色值 c 的蓝色值的等效方法:

float b1 = blue(c); // Simpler, but slower to calculate

简单，但是慢

float b2 = c & 0xFF; // Very fast to calculate

非常快

Syntax

blue(rgb)

Parameters

Returns

float

Related

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