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dx: add support for inverting all types of cursor (#9665)

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This commit introduces support for inverting all types of cursor.

To invert the display without re-rendering any text, we draw the cursor
into a command list and then compose the command list with the existing
renderer using the MASK_INVERT composition flag.

This wouldn't normally work with our renderer because there is no
_background_ color to invert in some cases (such as when acrylic is in
use.)

To work around that, we're taking advantage of @zadjii-msft's two-pass
cursor renderer.

To properly invert the cursor over a transparent background:
(Examples are given below for two cursor types, but this applies to all
of them.)

First, we'll draw a "backplate" in the user's requested background color
(with the alpha channel set to 0xFF). (`firstPass` == true)

    EMPTY BOX  FILLED BOX
    =====      =====
    =   =      =====
    =   =      =====
    =   =      =====
    =====      =====

Second, the glyph is drawn (outside of the cursor renderer).

    EMPTY BOX  FILLED BOX
    ==A==      ==A==
    =A A=      =A=A=
    AAAAA      AAAAA
    A   A      A===A
    A===A      A===A

Last, we'll draw the cursor again in all white and use that as the
*mask* for inverting the already-drawn pixels. (`firstPass` == false) (#
= mask, a = inverted A)

    EMPTY BOX  FILLED BOX
    ##a##      ##a##
    #A A#      #a#a#
    aAAAa      aaaaa
    a   a      a###a
    a###a      a###a

Related to #9610

## Validation Steps Performed
Manual visual validation in all configurations.
This commit is contained in:
Dustin L. Howett 2021-04-02 04:18:06 -07:00 committed by GitHub
parent fd99b012f5
commit 4b7d955012
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
2 changed files with 105 additions and 26 deletions
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1
.github/actions/spelling/expect/alphabet.txt vendored
View file

@ -1,3 +1,4 @@
AAAa
abcd
abcde
abcdef

130
src/renderer/dx/CustomTextRenderer.cpp
View file

@ -257,20 +257,23 @@ try
return S_FALSE;
}
const bool fInvert = !options.fUseColor;
// The normal, colored FullBox and legacy cursors are drawn in the first pass
// so they go behind the text.
// Inverted cursors are drawn in two passes.
// All other cursors are drawn in the second pass only.
if (!fInvert)
{
if (firstPass != (options.cursorType == CursorType::FullBox))
{
return S_FALSE;
}
}
// TODO GH#6338: Add support for `"cursorTextColor": null` for letting the
// cursor draw on top again.
// Only draw the filled box in the first pass. All the other cursors should
// be drawn in the second pass.
// | type==FullBox |
// firstPass | T | F |
// T | draw | skip |
// F | skip | draw |
if ((options.cursorType == CursorType::FullBox) != firstPass)
{
return S_FALSE;
}
// **MATH** PHASE
const til::size glyphSize{ til::math::flooring,
drawingContext.cellSize.width,
drawingContext.cellSize.height };
@ -294,15 +297,6 @@ try
}
CursorPaintType paintType = CursorPaintType::Fill;
Microsoft::WRL::ComPtr<ID2D1SolidColorBrush> brush{ drawingContext.foregroundBrush };
if (options.fUseColor)
{
// Make sure to make the cursor opaque
RETURN_IF_FAILED(d2dContext->CreateSolidColorBrush(til::color{ OPACITY_OPAQUE | options.cursorColor },
&brush));
}
switch (options.cursorType)
{
case CursorType::Legacy:
@ -332,12 +326,6 @@ try
{
// Use rect for lower line.
rect.top = rect.bottom - 1;
// Draw upper line directly.
D2D1_RECT_F upperLine = rect;
upperLine.top -= 2;
upperLine.bottom -= 2;
d2dContext->FillRectangle(upperLine, brush.Get());
break;
}
case CursorType::EmptyBox:
@ -353,6 +341,78 @@ try
return E_NOTIMPL;
}
// **DRAW** PHASE
Microsoft::WRL::ComPtr<ID2D1SolidColorBrush> brush;
Microsoft::WRL::ComPtr<ID2D1Image> originalTarget;
Microsoft::WRL::ComPtr<ID2D1CommandList> commandList;
if (!fInvert)
{
// Make sure to make the cursor opaque
RETURN_IF_FAILED(d2dContext->CreateSolidColorBrush(til::color{ OPACITY_OPAQUE | options.cursorColor },
&brush));
}
else
{
// CURSOR INVERSION
// We're trying to invert the cursor and the character underneath it without redrawing the text (as
// doing so would break up the run if it were part of a ligature). To do that, we're going to try
// to invert the content of the screen where the cursor would have been.
//
// This renderer, however, supports transparency. In fact, in its default configuration it will not
// have a background at all (it delegates background handling to somebody else.) You can't invert what
// isn't there.
//
// To properly invert the cursor in such a configuration, then, we have to play some tricks. Examples
// are given below for two cursor types, but this applies to all of them.
//
// First, we'll draw a "backplate" in the user's requested background color (with the alpha channel
// set to 0xFF). (firstPass == true)
//
// EMPTY BOX FILLED BOX
// ===== =====
// = = =====
// = = =====
// = = =====
// ===== =====
//
// Then, outside of _drawCursor, the glyph is drawn:
//
// EMPTY BOX FILLED BOX
// ==A== ==A==
// =A A= =A=A=
// AAAAA AAAAA
// A A A===A
// A===A A===A
//
// Last, we'll draw the cursor again in all white and use that as the *mask* for inverting the already-
// drawn pixels. (firstPass == false) (# = mask, a = inverted A)
//
// EMPTY BOX FILLED BOX
// ##a## ##a##
// #A A# #a#a#
// aAAAa aaaaa
// a a a###a
// a###a a###a
if (firstPass)
{
// Draw a backplate behind the cursor in the *background* color so that we can invert it later.
// We're going to draw the exact same color as the background behind the cursor
const til::color color{ drawingContext.backgroundBrush->GetColor() };
RETURN_IF_FAILED(d2dContext->CreateSolidColorBrush(color.with_alpha(255),
&brush));
}
else
{
// When we're drawing an inverted cursor on the second pass (foreground), we want to draw it into a
// command list, which we will then draw down with MASK_INVERT. We'll draw it in white,
// which will ensure that every component is masked.
RETURN_IF_FAILED(d2dContext->CreateCommandList(&commandList));
d2dContext->GetTarget(&originalTarget);
d2dContext->SetTarget(commandList.Get());
RETURN_IF_FAILED(d2dContext->CreateSolidColorBrush(COLOR_WHITE, &brush));
}
}
switch (paintType)
{
case CursorPaintType::Fill:
@ -376,6 +436,24 @@ try
return E_NOTIMPL;
}
if (options.cursorType == CursorType::DoubleUnderscore)
{
// Draw upper line directly.
D2D1_RECT_F upperLine = rect;
upperLine.top -= 2;
upperLine.bottom -= 2;
d2dContext->FillRectangle(upperLine, brush.Get());
}
if (commandList)
{
// We drew the entire cursor in a command list
// so now we draw that command list using MASK_INVERT over the existing image
RETURN_IF_FAILED(commandList->Close());
d2dContext->SetTarget(originalTarget.Get());
d2dContext->DrawImage(commandList.Get(), D2D1_INTERPOLATION_MODE_LINEAR, D2D1_COMPOSITE_MODE_MASK_INVERT);
}
return S_OK;
}
CATCH_RETURN()