如何在 Rebol/Red 中保留前几行的颜色
How to keep colors of previous lines in Rebol/Red
我正在尝试在修改后的绘图程序中绘制不同颜色的线条：
REBOL [title: "Paint"]
mycol: black
view layout [ size 1100x700
s: area 1060x600 white feel [
engage: func [f a e] [
if a = 'over [append s/effect/draw e/offset show s]
if a = 'up [append s/effect/draw 'line]
]
] effect [draw [pen mycol line]]
across
btn "Clear" 100x50 [s/effect/draw: copy [line] show s]
btn "Red" 100x50 [set [to-word mycol] red]
btn "blue" 100x50 [set [to-word mycol] blue]
btn "magenta" 100x50 [set [to-word mycol] magenta]
btn "green" 100x50 [set [to-word mycol] green]
btn "yellow" 100x50 [set [to-word mycol] yellow]
btn "orange" 100x50 [set [to-word mycol] orange]
btn "Quit" 100x50 [quit]
]
但是，当我select一种颜色时，区域中的所有线条都会改变颜色。我如何修改才能使前面的行保持相同的颜色？
一个最小的例子看起来像这样
view layout [
s: area white feel [
engage: func [f a e] [
if a = 'over [append s/effect/draw e/offset show s]
if a = 'up [append s/effect/draw 'line]
]
] effect [draw [pen blue line]]
btn "Clear" [s/effect/draw: copy [line] show s]
btn "Red" [append s/effect/draw [pen red line]]
]
所以你的脚本应该是
view layout [ size 1100x700
s: area 1060x600 white feel [
engage: func [f a e] [
if a = 'over [append s/effect/draw e/offset show s]
if a = 'up [append s/effect/draw 'line]
]
] effect [draw [pen black line]]
across
btn "Clear" 100x50 [s/effect/draw: copy [line] show s]
btn "Red" 100x50 [append s/effect/draw [pen red line]]
btn "blue" 100x50 [append s/effect/draw [pen blue line]]
btn "magenta" 100x50 [append s/effect/draw [pen magenta line]]
btn "green" 100x50 [append s/effect/draw [pen gree line]]
btn "yellow" 100x50 [append s/effect/draw [pen yellow line]]
btn "orange" 100x50 [append s/effect/draw [pen orange line]]
btn "Quit" 100x50 [quit]
]
Draw dialect是一张图的累积描述。在您的示例中，您只设置了一次笔颜色，此后所有线条都继承了该颜色。当您使用单词 mycol 设置笔的颜色时，一旦面部显示更新（上面代码中的 show s），您的所有线条都将设置为该单词所指的任何颜色。
这里可以分解一下，了解一些操作：
绘图
让我们用当前颜色在它自己的对象中启动绘图。
drawing: make object! [
image: []
color: black
use: func [new [tuple!]][
append image reduce ['pen color: new]
]
reset: does [
clear image
use color
]
reset
]
这里有管理绘图设置所需的一切：
image — 绘图本身（在 Draw 方言中）。
color — 当前画笔颜色。
use — 改变当前颜色并将其应用于绘图的函数。
重置 — 清除绘图。
Canvas
我们的 canvas 将是一个包含绘图的简单 BOX 面：
box 1060x600 white
effect reduce ['draw drawing/image]
并将对通过 Engage 函数传递的 down 和 over 操作作出反应：
feel [
engage: func [face action event] [
switch action [
down [append drawing/image 'line]
over [append drawing/image event/offset show face]
]
]
]
（我已将此处的参与参数更改为它们的全名——Rebol/Red 使用单字母单词几乎没有提高效率并且失去了很多表现力）
除了在 down 操作上开始新行外，这应该按照您示例中的参与功能工作。
操作
我们的 'Clear' 按钮使用 drawing 对象并重置 canvas（按钮的最老兄弟）：
btn "Clear" 100x50 [
drawing/reset
show first face/parent-face/pane
]
只是为了一点点界面糖，我们将使用切换来指示当前颜色。您可以使用 of 关键字在切换之间创建相互关系：
tog of 'color "Red" 100x50 [drawing/use red]
tog of 'color "Blue" 100x50 [drawing/use blue]
tog of 'color "Magenta" 100x50 [drawing/use magenta]
tog of 'color "Green" 100x50 [drawing/use green]
tog of 'color "Yellow" 100x50 [drawing/use yellow]
tog of 'color "Orange" 100x50 [drawing/use orange]
汇集在一起
可以用脚本将其包装起来：
Rebol [Title: "Paint"]
drawing: make object! [
image: []
color: black
use: func [new [tuple!]][
append image reduce ['pen color: new]
]
reset: does [
clear image
use color
]
reset
]
view layout [
box 1060x600 white
effect reduce ['draw drawing/image]
feel [
engage: func [face action event] [
switch action [
down [append drawing/image 'line]
over [append drawing/image event/offset show face]
]
]
]
across
btn "Clear" 100x50 [drawing/reset show face/parent-face/pane/1]
tog of 'color "Red" 100x50 [drawing/use red]
tog of 'color "Blue" 100x50 [drawing/use blue]
tog of 'color "Magenta" 100x50 [drawing/use magenta]
tog of 'color "Green" 100x50 [drawing/use green]
tog of 'color "Yellow" 100x50 [drawing/use yellow]
tog of 'color "Orange" 100x50 [drawing/use orange]
btn "Quit" 100x50 [unview]
]
我正在尝试在修改后的绘图程序中绘制不同颜色的线条：
REBOL [title: "Paint"]
mycol: black
view layout [ size 1100x700
s: area 1060x600 white feel [
engage: func [f a e] [
if a = 'over [append s/effect/draw e/offset show s]
if a = 'up [append s/effect/draw 'line]
]
] effect [draw [pen mycol line]]
across
btn "Clear" 100x50 [s/effect/draw: copy [line] show s]
btn "Red" 100x50 [set [to-word mycol] red]
btn "blue" 100x50 [set [to-word mycol] blue]
btn "magenta" 100x50 [set [to-word mycol] magenta]
btn "green" 100x50 [set [to-word mycol] green]
btn "yellow" 100x50 [set [to-word mycol] yellow]
btn "orange" 100x50 [set [to-word mycol] orange]
btn "Quit" 100x50 [quit]
]
但是，当我select一种颜色时，区域中的所有线条都会改变颜色。我如何修改才能使前面的行保持相同的颜色？
一个最小的例子看起来像这样
view layout [
s: area white feel [
engage: func [f a e] [
if a = 'over [append s/effect/draw e/offset show s]
if a = 'up [append s/effect/draw 'line]
]
] effect [draw [pen blue line]]
btn "Clear" [s/effect/draw: copy [line] show s]
btn "Red" [append s/effect/draw [pen red line]]
]
所以你的脚本应该是
view layout [ size 1100x700
s: area 1060x600 white feel [
engage: func [f a e] [
if a = 'over [append s/effect/draw e/offset show s]
if a = 'up [append s/effect/draw 'line]
]
] effect [draw [pen black line]]
across
btn "Clear" 100x50 [s/effect/draw: copy [line] show s]
btn "Red" 100x50 [append s/effect/draw [pen red line]]
btn "blue" 100x50 [append s/effect/draw [pen blue line]]
btn "magenta" 100x50 [append s/effect/draw [pen magenta line]]
btn "green" 100x50 [append s/effect/draw [pen gree line]]
btn "yellow" 100x50 [append s/effect/draw [pen yellow line]]
btn "orange" 100x50 [append s/effect/draw [pen orange line]]
btn "Quit" 100x50 [quit]
]
Draw dialect是一张图的累积描述。在您的示例中，您只设置了一次笔颜色，此后所有线条都继承了该颜色。当您使用单词 mycol 设置笔的颜色时，一旦面部显示更新（上面代码中的 show s），您的所有线条都将设置为该单词所指的任何颜色。
这里可以分解一下，了解一些操作：
绘图
让我们用当前颜色在它自己的对象中启动绘图。
drawing: make object! [
image: []
color: black
use: func [new [tuple!]][
append image reduce ['pen color: new]
]
reset: does [
clear image
use color
]
reset
]
这里有管理绘图设置所需的一切：
image — 绘图本身（在 Draw 方言中）。
color — 当前画笔颜色。
use — 改变当前颜色并将其应用于绘图的函数。
重置 — 清除绘图。
Canvas
我们的 canvas 将是一个包含绘图的简单 BOX 面：
box 1060x600 white
effect reduce ['draw drawing/image]
并将对通过 Engage 函数传递的 down 和 over 操作作出反应：
feel [
engage: func [face action event] [
switch action [
down [append drawing/image 'line]
over [append drawing/image event/offset show face]
]
]
]
（我已将此处的参与参数更改为它们的全名——Rebol/Red 使用单字母单词几乎没有提高效率并且失去了很多表现力）
除了在 down 操作上开始新行外，这应该按照您示例中的参与功能工作。
操作
我们的 'Clear' 按钮使用 drawing 对象并重置 canvas（按钮的最老兄弟）：
btn "Clear" 100x50 [
drawing/reset
show first face/parent-face/pane
]
只是为了一点点界面糖，我们将使用切换来指示当前颜色。您可以使用 of 关键字在切换之间创建相互关系：
tog of 'color "Red" 100x50 [drawing/use red]
tog of 'color "Blue" 100x50 [drawing/use blue]
tog of 'color "Magenta" 100x50 [drawing/use magenta]
tog of 'color "Green" 100x50 [drawing/use green]
tog of 'color "Yellow" 100x50 [drawing/use yellow]
tog of 'color "Orange" 100x50 [drawing/use orange]
汇集在一起
可以用脚本将其包装起来：
Rebol [Title: "Paint"]
drawing: make object! [
image: []
color: black
use: func [new [tuple!]][
append image reduce ['pen color: new]
]
reset: does [
clear image
use color
]
reset
]
view layout [
box 1060x600 white
effect reduce ['draw drawing/image]
feel [
engage: func [face action event] [
switch action [
down [append drawing/image 'line]
over [append drawing/image event/offset show face]
]
]
]
across
btn "Clear" 100x50 [drawing/reset show face/parent-face/pane/1]
tog of 'color "Red" 100x50 [drawing/use red]
tog of 'color "Blue" 100x50 [drawing/use blue]
tog of 'color "Magenta" 100x50 [drawing/use magenta]
tog of 'color "Green" 100x50 [drawing/use green]
tog of 'color "Yellow" 100x50 [drawing/use yellow]
tog of 'color "Orange" 100x50 [drawing/use orange]
btn "Quit" 100x50 [unview]
]