should make colormap images (palette images) OK. (#1864)

Author: GillesDuvert

src/pro/write_bmp.pro

@@ -96,11 +96,8 @@ endif else begin
         MAGICK_WRITE, mid,_image,rgb=rgb
         if (N_ELEMENTS(red) eq N_ELEMENTS(green) and $
             N_ELEMENTS(red) eq N_ELEMENTS(blue)) then begin
+            MAGICK_WRITEColorTable,mid,red,green,blue
             MAGICK_QUANTIZE,mid,long(N_ELEMENTS(red))
-            ;;
-            ;;  MAGICK_WRITEIndexes,mid,image
-            ;;  MAGICK_WRITEColorTable,mid,red,green,blue
-            ;;
             MAGICK_WRITEFILE, mid, filename, "BMP"
             MAGICK_CLOSE, mid
         endif        

src/pro/write_jpeg.pro

@@ -124,9 +124,9 @@ pro WRITE_JPEG, filename, image, true=true, $
   endif else begin
      mid=MAGICK_CREATE(im_size[0],im_size[1]) ; only 2 dimensions allowed here
                                 ; create a greyscale colormap
-     cmap=indgen(256)
-     MAGICK_WRITECOLORTABLE, mid,cmap,cmap,cmap
+;;     cmap=indgen(256)
      MAGICK_WRITE, mid, image
+;;     MAGICK_WRITECOLORTABLE, mid,cmap,cmap,cmap
      if (KEYWORD_SET(progressive)) then MAGICK_INTERLACE, mid, /LINEINTERLACE
      if (KEYWORD_SET(order)) then MAGICK_FLIP,mid
      q=75

src/pro/write_pict.pro

@@ -83,11 +83,8 @@ if (n eq 2) then begin
     MAGICK_FLIP,mid
     if(N_ELEMENTS(red) eq N_ELEMENTS(green) and $
        N_ELEMENTS(red) eq N_ELEMENTS(blue)) then begin
+        MAGICK_WRITEColorTable,mid,red,green,blue
         MAGICK_QUANTIZE,mid,long(N_ELEMENTS(red))
-        ;;
-        ;;                MAGICK_WRITEIndexes,mid,image
-        ;;                MAGICK_WRITEColorTable,mid,red,green,blue
-        ;;
         MAGICK_WRITEfile,mid,filename,"PICT"
         MAGICK_CLOSE,mid
     endif

src/pro/write_png.pro

@@ -126,9 +126,15 @@ if (nb_channels eq 1) then begin
       alpha=image*0+255
       MAGICK_MATTE, mid
    endif
-   ;;
-   MAGICK_WRITECOLORTABLE, mid, red, green, blue
+   ;; for some reason imagemagick does not use colortables when writing PNG files with 1 channel images.
+   ;; Better to do it by hand:
+   rr=image & gg=image & bb=image
+   for i=0,im_size[0]*im_size[1]-1 do rr[i]=red[rr[i]]
+   for i=0,im_size[0]*im_size[1]-1 do gg[i]=green[gg[i]]
+   for i=0,im_size[0]*im_size[1]-1 do bb[i]=blue[bb[i]]
+   image=transpose([[[rr]],[[gg]],[[bb]]],[2,0,1])
    MAGICK_WRITE, mid, image, rgb=rgb
+;;   MAGICK_WRITECOLORTABLE, mid, red, green, blue
    if (KEYWORD_SET(order)) then MAGICK_FLIP, mid
    MAGICK_WRITEFILE, mid, filename, "PNG"
    MAGICK_CLOSE, mid

src/pro/write_ppm.pro

@@ -41,8 +41,8 @@ pro write_ppm, file, image,  help = help
   if sz[0] eq 2 then begin      ; PGM
      mid = magick_create(sz[1], sz[2])
      cmap = indgen(256)
-     magick_writecolortable, mid, cmap, cmap, cmap
      magick_write, mid, reverse(image, 2)
+     magick_writecolortable, mid, cmap, cmap, cmap
      magick_writefile, mid, file, 'PGM'
   endif else if sz[0] eq 3 && sz[1] eq 3 then begin ; PPM
      mid = magick_create(sz[2], sz[3])