6 deleted 4 characters in body
source | link

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


As the @JThe version is derived from J.M.'s promption of Raster

aGraphics[{Opacity[0.5], =
  Raster[{Range[0, 1, 0.01];
Graphics[{Opacity[.5]1/100]}, 
 {{0, Raster[Array[a0}, &{1, Length@a]1}}, 
   ColorFunction -> "Rainbow"]}]

enter image description here

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


As the @J.M.'s promption of Raster

a = Range[0, 1, 0.01];
Graphics[{Opacity[.5], 
  Raster[Array[a &, Length@a], ColorFunction -> "Rainbow"]}]

enter image description here

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


The version is derived from J.M.

Graphics[{Opacity[0.5], 
  Raster[{Range[0, 1, 1/100]}, {{0, 0}, {1, 1}}, 
   ColorFunction -> "Rainbow"]}]

enter image description here

5 deleted 1 character in body
source | link

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


As the @J.M.'s promption of Raster

Graphics[{Opacity[.5], 
  Raster[Array[(a = Range[0, 1, 0.01])01];
Graphics[{Opacity[.5], 
  Raster[Array[a &, Length@a], 
   ColorFunction -> "Rainbow"]}]

enter image description here

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


As the @J.M.'s promption of Raster

Graphics[{Opacity[.5], 
  Raster[Array[(a = Range[0, 1, 0.01]) &, Length@a], 
   ColorFunction -> "Rainbow"]}]

enter image description here

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


As the @J.M.'s promption of Raster

a = Range[0, 1, 0.01];
Graphics[{Opacity[.5], 
  Raster[Array[a &, Length@a], ColorFunction -> "Rainbow"]}]

enter image description here

4 added 270 characters in body
source | link

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


As the @J.M.'s promption of Raster

Graphics[{Opacity[.5], 
  Raster[Array[(a = Range[0, 1, 0.01]) &, Length@a], 
   ColorFunction -> "Rainbow"]}]

enter image description here

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here

Perhaps ou mean this?

    Show[SetAlphaChannel[LinearGradientImage["Rainbow"], 0.5], Axes -> True]

enter image description here


As the @J.M.'s promption of Raster

Graphics[{Opacity[.5], 
  Raster[Array[(a = Range[0, 1, 0.01]) &, Length@a], 
   ColorFunction -> "Rainbow"]}]

enter image description here

3 added 25 characters in body
source | link
2 added 22 characters in body
source | link
1
source | link