Weird colorbar

I generated some plots and wanted to add colorbar to them and it partially works.
weirdBar
My code to generate this bar in CImGui is:

low=colorant"navyblue";
medium=colorant"limegreen";
high=colorant"yellow";
barImage=Array{RGB{Normed{UInt8,8}}}(undef,1,3)

barImage[1]=high
barImage[2]=medium
barImage[3]=low

barImage=unsafe_wrap(Array{UInt8,3}, convert(Ptr{UInt8}, pointer(barImage)), (Cint(3), Cint(1), Cint(3)))
ImGui_ImplOpenGL3_ReplaceStrechedImageTexture(color_bar_id, barImage, 1, 3; format = GL_RGB)

Where ReplaceStrechedImageTexture is my own added function(however the problem shouldn’t be caused by this):

function ImGui_ImplOpenGL3_ReplaceStrechedImageTexture(id, image_data, image_width, image_height; format=GL_RGBA, type=GL_UNSIGNED_BYTE)
    global g_ImageTexture
    glBindTexture(GL_TEXTURE_2D, g_ImageTexture[id])
    glTexImage2D(GL_TEXTURE_2D, 0, format, GLsizei(image_width), GLsizei(image_height), 0, format, type, image_data)
end

The problem is with lower part of colorbar.
weirdBar
From my point of view and with image analysis, this “navyblue” color should be the lower part(I don’t know from this white/grey part on the bottom has been generated), because the lower values occur on the second and fourth quarter of plot.