1 /***************************************************************************
2 * Copyright (c) 2024 Microsoft Corporation
3 *
4 * This program and the accompanying materials are made available under the
5 * terms of the MIT License which is available at
6 * https://opensource.org/licenses/MIT.
7 *
8 * SPDX-License-Identifier: MIT
9 **************************************************************************/
10
11
12 /**************************************************************************/
13 /**************************************************************************/
14 /** */
15 /** GUIX Component */
16 /** */
17 /** Display Management (Display) */
18 /** */
19 /**************************************************************************/
20 #define GX_SOURCE_CODE
21
22
23 #include "gx_api.h"
24 #include "gx_display.h"
25
26 /**************************************************************************/
27 /* */
28 /* FUNCTION RELEASE */
29 /* */
30 /* _gx_display_driver_32argb_rotated_pixel_blend PORTABLE C */
31 /* 6.1.4 */
32 /* AUTHOR */
33 /* */
34 /* Kenneth Maxwell, Microsoft Corporation */
35 /* */
36 /* DESCRIPTION */
37 /* */
38 /* Rotated Pixel blend function for 32argb color format. */
39 /* */
40 /* INPUT */
41 /* */
42 /* context Drawing context */
43 /* x X coordinate */
44 /* y Y coordinate */
45 /* color Color of line to write */
46 /* alpha blending value 0 to 255 */
47 /* */
48 /* OUTPUT */
49 /* */
50 /* None */
51 /* */
52 /* CALLS */
53 /* */
54 /* None */
55 /* */
56 /* CALLED BY */
57 /* */
58 /* GUIX Internal Code */
59 /* */
60 /* RELEASE HISTORY */
61 /* */
62 /* DATE NAME DESCRIPTION */
63 /* */
64 /* 02-02-2021 Kenneth Maxwell Initial Version 6.1.4 */
65 /* */
66 /**************************************************************************/
_gx_display_driver_32argb_rotated_pixel_blend(GX_DRAW_CONTEXT * context,INT x,INT y,GX_COLOR fcolor,GX_UBYTE alpha)67 VOID _gx_display_driver_32argb_rotated_pixel_blend(GX_DRAW_CONTEXT *context, INT x, INT y, GX_COLOR fcolor, GX_UBYTE alpha)
68 {
69 GX_UBYTE falpha, fred, fgreen, fblue;
70 GX_UBYTE balpha, bred, bgreen, bblue;
71 GX_UBYTE oalpha;
72 ULONG bcolor;
73 ULONG *put;
74 INT combined_alpha;
75
76
77 falpha = ALPHAVAL_32BPP(fcolor);
78 falpha = (GX_UBYTE)((falpha * alpha) / 255);
79
80 /* Is the pixel non-transparent? */
81 if (falpha > 0)
82 {
83
84 /* Calculate address of pixel. */
85 put = (ULONG *)context -> gx_draw_context_memory;
86
87 GX_SWAP_VALS(x, y);
88 if (context -> gx_draw_context_display -> gx_display_rotation_angle == GX_SCREEN_ROTATION_CW)
89 {
90 y = context -> gx_draw_context_canvas -> gx_canvas_x_resolution - y - 1;
91 }
92 else
93 {
94 x = context -> gx_draw_context_canvas -> gx_canvas_y_resolution - x - 1;
95 }
96
97 put += context -> gx_draw_context_pitch * y;
98 put += x;
99
100 /* No need to blend if alpha value is 255. */
101 if (falpha == 255)
102 {
103 *put = (ULONG)fcolor;
104 return;
105 }
106
107 /* Split foreground into alpha, red, green, and blue components. */
108 fred = REDVAL_32BPP(fcolor);
109 fgreen = GREENVAL_32BPP(fcolor);
110 fblue = BLUEVAL_32BPP(fcolor);
111
112 /* Read background color. */
113 bcolor = *put;
114
115 /* Split background color into red, green, and blue components. */
116 balpha = ALPHAVAL_32BPP(bcolor);
117 bred = REDVAL_32BPP(bcolor);
118 bgreen = GREENVAL_32BPP(bcolor);
119 bblue = BLUEVAL_32BPP(bcolor);
120
121 /* Background alpha is inverse of foreground alpha. */
122 combined_alpha = (falpha * balpha) / 0xff;
123
124 /* Blend foreground and background, each color channel. */
125 oalpha = (GX_UBYTE)(falpha + balpha - combined_alpha);
126 fred = (GX_UBYTE)((fred * falpha + bred * balpha - bred * combined_alpha) / oalpha);
127 fgreen = (GX_UBYTE)((fgreen * falpha + bgreen * balpha - bgreen * combined_alpha) / oalpha);
128 fblue = (GX_UBYTE)((fblue * falpha + bblue * balpha - bblue * combined_alpha) / oalpha);
129
130 /* Re-assemble into 16-bit color and write it out. */
131 *put = (ULONG)ASSEMBLECOLOR_32ARGB(oalpha, fred, fgreen, fblue);
132 }
133 }
134
135
