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Raster[{{a₁₁,a₁₂,…},…}]

是一个二维图形元素，用来表示一个灰度单元的矩形阵列.

Raster[{{{r₁₁,g₁₁,b₁₁},…},…}]

表示一个 RGB 颜色单元组成的阵列.

Raster[{{{r₁₁,g₁₁,b₁₁,α₁₁},…},…}]

表示有不透明度 α_ij 的颜色单元组成的阵列.

Raster[{{{a₁₁,α₁₁},…},…}]

表示有指定不透明度的灰度单元组成的阵列.

Raster

Raster[{{a₁₁,a₁₂,…},…}]

是一个二维图形元素，用来表示一个灰度单元的矩形阵列.

Raster[{{{r₁₁,g₁₁,b₁₁},…},…}]

表示一个 RGB 颜色单元组成的阵列.

Raster[{{{r₁₁,g₁₁,b₁₁,α₁₁},…},…}]

表示有不透明度 α_ij 的颜色单元组成的阵列.

Raster[{{{a₁₁,α₁₁},…},…}]

表示有指定不透明度的灰度单元组成的阵列.

范例

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基本范例 (4)

灰度单元组成的矩形阵列：

Wolfram Language code: Graphics[Raster[{{0, 0.2, 0.4}, {0.6, 0.8, 1}}]]

RGB 颜色单元组成的阵列：

Wolfram Language code: Graphics[Raster[{{{0, 1, 1}, {1, 0, 1}, {1, 1, 0}}, {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}}]]

有不透明度的灰度单元组成的阵列：

Wolfram Language code: Graphics[{{Red, Disk[{5, 5}, 4]}, Raster[Table[{1 - x, y}, {x, .1, 1, .1}, {y, .1, 1, .1}]]}]

有不透明度的 RGB 单元组成的阵列：

Wolfram Language code: Graphics[{{Red, Disk[{5, 5}, 4]}, Raster[Table[{x, y, x, y}, {x, .1, 1, .1}, {y, .1, 1, .1}]]}]

范围 (14)

Raster 详细说明 (3)

对于一个 × 矩形，栅格占用从 {0,0} 到 {m,n} 的矩形：

Wolfram Language code: a = {{0, 0.2, 0.4}, {0.6, 0.8, 1}};

Wolfram Language code: Graphics[Raster[a], Frame -> True, FrameTicks -> False]

用普通左标明确指定栅格的形状：

Wolfram Language code: Graphics[Raster[a, {{0, 1}, {5, 4}}], PlotRange -> {{0, 5}, {0, 5}}, Frame -> True]

用 Scaled 和 ImageScaled：

Wolfram Language code: a = {{0, 0.2, 0.4}, {0.6, 0.8, 1}};

Wolfram Language code:

Graphics[Raster[a, {Scaled[{0, .3}], Scaled[{1, .7}]}], PlotRange -> {{0, 5}, {0, 5}}, 
Frame -> True]

Wolfram Language code:

Graphics[Raster[a, {ImageScaled[{0, .3}], ImageScaled[{1, .7}]}], PlotRange -> {{0, 5}, {0, 5}}, 
Frame -> True]

用 Offset：

Wolfram Language code: a = {{0, 0.2, 0.4}, {0.6, 0.8, 1}};

Wolfram Language code:

Graphics[Raster[a, {Offset[{10, 10}, {0, 0}], Offset[{-10, -10}, {5, 5}]}], PlotRange -> {{0, 5}, {0, 5}}, 
Frame -> True]

Raster 样式 (11)

标量矩阵的栅格缺省下用灰度显示：

Wolfram Language code: a = {{0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}};

Wolfram Language code: Graphics[Raster[a], Frame -> True, FrameTicks -> False]

Wolfram Language code: Graphics[Raster[a, ColorFunction -> GrayLevel], Frame -> True, FrameTicks -> False]

0 到 1 范围外的值通常剪切为 0 或 1：

Wolfram Language code: a = {{-0.4, -0.2, 0, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4}};

Wolfram Language code: Graphics[Raster[a], Frame -> True, FrameTicks -> False]

指定值的范围：

Wolfram Language code: a = {{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};

Wolfram Language code: Graphics[Raster[a, Automatic, {0, 10}], Frame -> True, FrameTicks -> False]

剪切指定范围外的值：

Wolfram Language code: a = {{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};

Wolfram Language code: Graphics[Raster[a, Automatic, {2, 8}], Frame -> True, FrameTicks -> False]

数对组成的数组可以视为有不透明度的灰度：

Wolfram Language code: a = {{{0, .2}, {0, .4}, {0, .5}, {0, .6}, {0, .8}, {0, 1}}};

Wolfram Language code: Graphics[Raster[a], Background -> Cyan]

三元数组的栅格缺省下用 RGB 色：

Wolfram Language code: a = {{{1, 0, 0}, {0, 1, 0}, {0, 0, 1}}, {{.5, 0, 0}, {0, .5, 0}, {0, 0, .5}}};

Wolfram Language code: Graphics[Raster[a]]

Wolfram Language code: Graphics[Raster[a, ColorFunction -> RGBColor]]

四元数组视为有不透明度的 RGB 值：

Wolfram Language code: a = {{{1, 0, 0, 1}, {0, 1, 0, 1}, {0, 0, 1, 1}}, {{1, 0, 0, .5}, {0, 1, 0, .5}, {0, 0, 1, .5}}};

Wolfram Language code: Graphics[Raster[a], Background -> Cyan]

对标量矩阵用 Hue 值：

Wolfram Language code: a = {{0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}};

Wolfram Language code: Graphics[Raster[a, ColorFunction -> Hue]]

使用用户定义的函数：

Wolfram Language code: a = {{0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}};

Wolfram Language code: Graphics[Raster[a, ColorFunction -> (Blend[{Red, Blue}, #]&)]]

用指定范围的颜色函数：

Wolfram Language code: a = {{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}};

Wolfram Language code: Graphics[Raster[a, Automatic, {0, 10}, ColorFunction -> (Blend[{Red, Blue}, #]&)]]

用预定义的梯度：

Wolfram Language code: a = {{0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1}};

Wolfram Language code: Graphics[Raster[a, ColorFunction -> "AvocadoColors"]]

推广和延伸 (1)

任何 Wolfram 语言表达式可以应用到一个颜色函数中：

Wolfram Language code: a = {{x, y, y, z, z, z, x}};

Wolfram Language code: Graphics[Raster[a, ColorFunction -> (Switch[#, x, Red, y, Green, z, Blue]&)]]

Wolfram Language code: b = {{"Tomato", "Gold", "LawnGreen", "SteelBlue"}};

Wolfram Language code: Graphics[Raster[b, ColorFunction -> (ColorData["HTML", #]&)]]

选项 (4)

ColorFunction (4)

每个函数用灰度层：

Wolfram Language code: Graphics[Raster[{{0, 0.2, 0.4}, {0.6, 0.8, 1}}, ColorFunction -> GrayLevel]]

用 Hue 值对栅格单元着色：

Wolfram Language code: Graphics[Raster[{{0, 0.2, 0.4}, {0.6, 0.8, 1}}, ColorFunction -> Hue]]

使用用户定义的颜色函数：

Wolfram Language code: Graphics[Raster[{{0, 0.2, 0.4}, {0.6, 0.8, 1}}, ColorFunction -> (RGBColor[#, #, 1 - #]&)]]

用一个预定义的梯度：

Wolfram Language code: Graphics[Raster[{Range[0, 1, .1]}, ColorFunction -> "TemperatureMap"]]

应用 (3)

用栅格作为墙纸：

Wolfram Language code: r = Raster[Table[i, {i, 100}, {j, 100}], {Scaled[{0, 0}], Scaled[{1, 1}]}, {1, 100}, ColorFunction -> "Pastel"];

Wolfram Language code: Plot[{Sin[x], Cos[x], Csc[x]}, {x, 0, 10}, Prolog -> r, PlotStyle -> Thick]

用 ExampleData 获得一个实验 RGB 栅格：

Wolfram Language code: rgb = Reverse[ExampleData[{"TestImage", "Sailboat"}, "Data"] / 255.];

Wolfram Language code: Graphics[Raster[rgb]]

将 RGB 转换为灰度：

Wolfram Language code: gray = Map[{.3, .59, .11}.#&, rgb, {2}];

Wolfram Language code: Graphics[Raster[gray]]

用 ListCorrelate 做一个滤波，然后显示它：

Wolfram Language code: ker = {{1, 0, -1}, {1, 0, -1}, {1, 0, -1}};

Wolfram Language code: f = ListCorrelate[ker, gray];

Wolfram Language code: Graphics[Raster[f, Automatic, MinMax[f] / 4, ColorFunction -> "TemperatureMap"]]

定义一个简单的栅格密度的图形函数：

Wolfram Language code:

rasterDensityPlot[f_, {xs_, xmin_, xmax_}, {ys_, ymin_, ymax_}, opts : OptionsPattern[rasterDensityPlot]] := Module[{raw, ppts, cf, zmin, zmax}, {ppts, cf} = OptionValue[{PlotPoints, ColorFunction}];raw = Table[f /. {xs -> j, ys -> i}, {i, ymin, ymax, (ymax - ymin) / (ppts - 1)}, {j, xmin, xmax, (xmax - xmin) / (ppts - 1)}];zmin = Min[raw];zmax = Max[raw];Graphics[Raster[raw, {{xmin, ymin}, {xmax, ymax}}, {zmin, zmax}, ColorFunction -> cf], FilterRules[{opts}, Options[Graphics]], AspectRatio -> 1, Frame -> True]]

设置函数的选项：

Wolfram Language code: Options[rasterDensityPlot] = Sort@Join[{PlotPoints -> 50, ColorFunction -> "LakeColors"}, Options[Graphics]];

结果：

Wolfram Language code: rasterDensityPlot[x Sin[y], {x, -5, 5}, {y, 0, 10}, ColorFunction -> "AvocadoColors"]

Wolfram Language code: rasterDensityPlot[Sin[x] Sin[ y], {x, -4, 4}, {y, -4, 4}, ColorFunction -> "SunsetColors"]

属性和关系 (7)

Rotate 可以应用到一个栅格上：

Wolfram Language code: Graphics[Rotate[Raster[Table[{i, j, .5}, {i, 0, 1, .1}, {j, 0, 1, .1}]], Pi / 6]]

可视化离散数据时用 ArrayPlot：

Wolfram Language code: data = CellularAutomaton[30, {{1}, 0}, 20];

Wolfram Language code: {ArrayPlot[data], Graphics[Raster[data]]}

可视化连续数据时用 ListDensityPlot：

Wolfram Language code: data = Table[Exp[-(x ^ 2 + y ^ 2)], {x, -1.5, 1.5, .1}, {y, -1.5, 1.5, 0.1}];

Wolfram Language code: {ListDensityPlot[data, FrameTicks -> None], Graphics[Raster[data]]}

可视化高度数据时用 ReliefPlot：

Wolfram Language code: data = Table[Evaluate[Sum[Sin[RandomReal[5, 2].{x, y}], {10}]], {x, 0, 10, .04}, {y, 0, 10, .04}];

Wolfram Language code: {ReliefPlot[data], Graphics[Raster[data, Automatic, {Min[data], Max[data]}]]}

Rasterize 可以从任何表达式中产生一个栅格图形：

Wolfram Language code: Rasterize[x ^ 2 + y ^ 2 == 1, "Graphics"]