drawing images on text face after displayed = "highlighting text"

rebol [] stylize/master [ my-text: text with [ highlights: [] ; custom facet init: [ pane: copy [] ] add-highlight: func [start end][ append append highlights start end refresh-highlights show self ] highlight-box: make-face/spec 'box [ size: 50x18 effect: [merge multiply yellow] ; translucent ] refresh-highlights: has [n][ n: 0 foreach [start end] highlights [ n: n + 1 if n > length? pane [ append pane make highlight-box [] ] pane/:n/offset: 30x22 * (n - 1) ; (use CARET-TO-OFFSET here etc.) ] clear skip pane n ; remove old highlights ] feel: make feel [ redraw: func [face action position][ ;face/refresh-highlights ] ] ] ] view layout [ my-text: my-text 400x300 {Hello how are you going^/Just wonderful thankyou.} btn "Add highlight" [my-text/add-highlight 10 20] ]

I use almost the same method.

You can probably do that with the SHAPE command in DRAW. To ensure accurate painting, I would use SIZE-TEXT as it can accurately detemine the width and height of the area you need to paint per row. My implementation uses plain boxes and then SIZE-TEXT to calculate the size of one highlight box. It works for all font sizes I've tested so far. My only problem right now is detecting the start and end point of multi-line text as I want a more accurate depiction of the selected text. To detect multiple line highlights: If the Y position of caret-to-offset is not identical for start and end position, then you are using multiple lines. -- Regards, Henrik Mikael Kristensen

You shouldn't use size-text on the original face. Something like: size-text make t [size: 2000x50 text: highlighted-text] Explanation: You make a copy of the original text face for measurement purposes, and then let it only contain the highlighted text. (I guess View needs to render the text internally to return the size of it.) You then need the exact same text attributes (font and para) for it to measure the size correctly. You also need a rather big size in order for the text in the new face to flow correctly to avoid unintended linebreaks as we want the text to match the original. -- Regards, Henrik Mikael Kristensen

My code so far (stolen from your original code submission): rebol [] pad: 20x30 set-highlight: func [ "Sets the highlight boxes in the given text face" face [object!] strings [block!] "Block of one or multiple string pairs describing the highlight start and end points" /no-show /local access ] [ if all [ access: get in face 'access in access 'set-face* ] [ access/set-highlight* face strings ] if not no-show [show face] face ] get-highlight: func [face [object!]] [ ; unimplemented ] window: layout [ style hl-text text with [ pane: make block! [] hl: none ; a single highlight face hl-face: make face [ color: 255.0.0 edge: none para: make para [origin: 0 margin: 0] effect: [gradient 0x1 255.128.0 255.0.0] ; just to make it look a little cooler ] ; the pane which stores all highlight faces hl-pane: make face [color: none pane: make block! []] ; the position in pane for the highlight pane as used by set-highlight* hl-pane-block: none make-hl-face: func [face str pos sz] [ append face/hl-pane-block make face/hl-face [offset: pos - 2 size: sz text: str] ] split-lines: make block! [] access: make access [ set-highlight*: func [face [object!] strings [block!] /local pos end-pos split-lines str sz done] [ face/hl: strings clear face/hl-pane-block ; create highlight boxes foreach [start end] face/hl [ ; paint a box for each highlight by finding the position on where to paint it using caret-to-offset to get the position. ; is the highlight split over multiple lines? ; the end-pos can't be used here, we need to do the split thing before calculating positions str: copy/part start end sz: size-text make face/hl-face [size: 2000x50 text: str] pos: caret-to-offset face start end-pos: caret-to-offset face end either pos/y <> end-pos/y [ ; multiple lines ; ---------- The code in this block is not working correctly ------------ ; paint one box per line for multiple line highlights ; that means that each line must paint right from start or beginning of line to either the end of highlight or end of line ; generate split-lines list of all indexes required for painting the lines clear split-lines line-pos: start ; we should be able to use the line list, but something is not right here. ; the line list is not set, but it would be manipulated by something, so we should figure out what that is until [ ; calculate start of line or none sol: ; calculate end of line or none eol: case [ ; start of line to end of line all [sol eol] [repend split-lines [sol eol] false] ; start of text to end of line all [none? sol eol] [repend split-lines [start eol] false] ; start of line to end of text all [sol none? eol] [repend split-lines [sol end] true] ] ] foreach [start end] split-lines [ str: copy/part start end sz: size-text make face/hl-face [size: 2000x50 text: str] pos: caret-to-offset face start make-hl-face face str pos sz ] ][ make-hl-face face str pos probe sz ] ] show face ] ] append init [ ; prepare the highlight face to have the right font hl-face/font: make font [offset: 0x0 color: white] unless all [block? pane none? pane] [pane: make block! []] ; position the hl-pane hl-pane/color: none hl-pane/size: size ; perhaps size optimize it later hl-pane/offset: offset append pane hl-pane ; prepare hl-pane-block hl-pane-block: get in last pane 'pane ] ] bx: box red 0x0 panel: panel [ tt: hl-text 500 font-size 12 {Here is a simple example how to use DRAW dialect for into alpha channel of the image. I think with the function make-alpha (bellow in the example) you can draw almost any kind of transparent shape though it is not the fastest method....IMO the possibility to use DRAW pens for alpha channel should be done at Rebol's native level} t: text 400 {Here is a simple example how to use DRAW dialect for e-alpha (bellow in the example) you can draw almost any kind of transparent shape though it is not the fastest method....IMO the possiinto alpha channel of the image. I think with the function make-alpha (bellow in the example) you can draw almost any kind of transparent shape though it is not the fastest method....IMO the possibility to use DRAW pens for alpha channel should be done at Rebol's native level} text 500 {can draw almost any kind of transparent shape though it is not the fastest method....IMO the possibility to use DRAW pens for alpha channel should be done at Rebol's naHere is a simple example how to use DRAW dialect for into alpha channel of the image. I think with the function make-alpha (bellow in the example) you can draw almost any kind of transparent shape though it is not the fastest method....IMO the possibility to use DRAW pens for alpha channel should be done at Rebol's native level}] button "Highlight" [foreach face panel/pane [if face/style = 'text [ system/view/focal-face: face system/view/highlight-start: find face/text "into alpha channel of the image" system/view/highlight-end: find/tail face/text "into alpha channel of the image" show face ]]] button "Paint" [foreach face panel/pane [if face/style = 'text [ keyword: "transparent" xy: caret-to-offset face find face/text keyword bx/offset: face/offset + pad + xy bx/size: as-pair (5.9 * length? keyword) 15 show face ]]] button "Box highlight" [ set-highlight tt reduce [ ; one start and end highlight component per line find tt/text "IMO" skip find tt/text "IMO" 10 find tt/text "native" skip find tt/text "native" 4 ] ] ] view window -- Regards, Henrik Mikael Kristensen

Hidden too deep I think. But can be worked around, I think.

Yes, it is.

section?

You can't do it in place. I've obtained this by use of workarounds which you can see working pretty well in demo-caret-to-offset-patch.r and test-caret-to-offset-patch.r See my lengthy investigations in these files. http://anton.wildit.net.au/rebol/doc/field-text-draw.r http://anton.wildit.net.au/rebol/view/draw/smooth-font-scaling.r http://anton.wildit.net.au/rebol/patch/demo-caret-to-offset-patch.r http://anton.wildit.net.au/rebol/patch/test-caret-to-offset-patch.r Especially those last two files. Regards, Anton.

Thanks for the reply, Anton. I was wondering about line-list myself and how useless it is for this case. Now I don't need to waste any more hours on that. :-) -- Regards, Henrik Mikael Kristensen