Initial image support

* png: add missing filters, various decoder fixes
* term: fix kitty response interpretation, add support for kitty image
  detection
* buffer, pager: initial image display support

Emphasis on "initial"; it only "works" with kitty output and PNG input.
Also, it's excruciatingly slow, and repaints images way too often.

Left undocumented intentionally it for now, until it actually becomes
useful.  In the meantime, adventurous users can find out themselves why:

[[siteconf]]
url = "https://.*"
images = true

1 files changed, 16 insertions, 6 deletions

diff --git a/src/server/buffer.nim b/src/server/buffer.nim
index 10d1cce0..56ad946f 100644
--- a/src/server/buffer.nim
+++ b/src/server/buffer.nim
@@ -26,6 +26,7 @@ import html/enums
 import html/env
 import html/event
 import html/formdata as formdata_impl
+import img/bitmap
 import io/bufreader
 import io/bufstream
 import io/bufwriter
@@ -91,6 +92,7 @@ type
     ishtml: bool
     firstBufferRead: bool
     lines: FlexibleGrid
+    images: seq[PosBitmap]
     request: Request # source request
     attrs: WindowAttributes
     window: Window
@@ -648,7 +650,9 @@ proc findNextMatch*(buffer: Buffer; regex: Regex; cursorx, cursory: int;
       break
     inc y
 
-proc gotoAnchor*(buffer: Buffer): Opt[tuple[x, y: int]] {.proxy.} =
+type GotoAnchorResult* = Opt[tuple[x, y: int]]
+
+proc gotoAnchor*(buffer: Buffer): GotoAnchorResult {.proxy.} =
   if buffer.document == nil:
     return err()
   let anchor = buffer.document.findAnchor(buffer.url.anchor)
@@ -673,7 +677,8 @@ proc do_reshape(buffer: Buffer) =
     buffer.prevStyled = nil
   let styledRoot = buffer.document.applyStylesheets(uastyle,
     buffer.userstyle, buffer.prevStyled)
-  buffer.lines.renderDocument(buffer.bgcolor, styledRoot, addr buffer.attrs)
+  buffer.lines.renderDocument(buffer.bgcolor, styledRoot, addr buffer.attrs,
+    buffer.images)
   buffer.prevStyled = styledRoot
 
 proc processData0(buffer: Buffer; data: openArray[char]): bool =
@@ -1718,11 +1723,11 @@ proc readCanceled*(buffer: Buffer): bool {.proxy.} =
 proc findAnchor*(buffer: Buffer; anchor: string): bool {.proxy.} =
   return buffer.document != nil and buffer.document.findAnchor(anchor) != nil
 
-type GetLinesResult* = tuple[
-  numLines: int,
-  lines: seq[SimpleFlexibleLine],
+type GetLinesResult* = tuple
+  numLines: int
+  lines: seq[SimpleFlexibleLine]
   bgcolor: CellColor
-]
+  images: seq[PosBitmap]
 
 proc getLines*(buffer: Buffer; w: Slice[int]): GetLinesResult {.proxy.} =
   var w = w
@@ -1736,6 +1741,11 @@ proc getLines*(buffer: Buffer; w: Slice[int]): GetLinesResult {.proxy.} =
     result.lines.add(line)
   result.numLines = buffer.lines.len
   result.bgcolor = buffer.bgcolor
+  if buffer.config.images:
+    for image in buffer.images:
+      if image.y <= w.b and
+          image.y + int(image.bmp.height) div buffer.attrs.ppl >= w.a:
+        result.images.add(image)
 
 proc markURL*(buffer: Buffer; schemes: seq[string]) {.proxy.} =
   if buffer.document == nil or buffer.document.body == nil: