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
21 #define GX_SOURCE_CODE
22
23 /* Include necessary system files. */
24
25 #include "gx_api.h"
26 #include "gx_display.h"
27 /**************************************************************************/
28 /* */
29 /* FUNCTION RELEASE */
30 /* */
31 /* _gx_display_driver_4bpp_vertical_line_draw PORTABLE C */
32 /* 6.1 */
33 /* AUTHOR */
34 /* */
35 /* Kenneth Maxwell, Microsoft Corporation */
36 /* */
37 /* DESCRIPTION */
38 /* */
39 /* Vertical line draw function for 4bpp display driver. */
40 /* */
41 /* INPUT */
42 /* */
43 /* context Drawing context */
44 /* ystart y-coord of top endpoint */
45 /* yend y-coord of bottom endpoint */
46 /* xpos x-coord of left edge */
47 /* width width of the line */
48 /* color Color of line to write */
49 /* */
50 /* OUTPUT */
51 /* */
52 /* None */
53 /* */
54 /* CALLS */
55 /* */
56 /* None */
57 /* */
58 /* CALLED BY */
59 /* */
60 /* GUIX Internal Code */
61 /* */
62 /* RELEASE HISTORY */
63 /* */
64 /* DATE NAME DESCRIPTION */
65 /* */
66 /* 05-19-2020 Kenneth Maxwell Initial Version 6.0 */
67 /* 09-30-2020 Kenneth Maxwell Modified comment(s), */
68 /* resulting in version 6.1 */
69 /* */
70 /**************************************************************************/
_gx_display_driver_4bpp_vertical_line_draw(GX_DRAW_CONTEXT * context,INT ystart,INT yend,INT xpos,INT width,GX_COLOR color)71 VOID _gx_display_driver_4bpp_vertical_line_draw(GX_DRAW_CONTEXT *context, INT ystart, INT yend, INT xpos, INT width, GX_COLOR color)
72 {
73 INT row;
74 INT column;
75 GX_UBYTE *put;
76 GX_UBYTE *putrow;
77 GX_UBYTE mask;
78 GX_UBYTE pixel;
79 INT stride;
80
81 /* Get row pitch in bytes. */
82 stride = (context -> gx_draw_context_pitch + 1) >> 1;
83 pixel = (GX_UBYTE)(color & 0x0f);
84 pixel |= (GX_UBYTE)(pixel << 4);
85
86 /* pick up starting address of canvas memory */
87 putrow = (GX_UBYTE *)context -> gx_draw_context_memory;
88 putrow += ystart * stride;
89 putrow += (xpos >> 1);
90
91 /* draw line from top to bottom */
92 for (row = ystart; row <= yend; row++)
93 {
94 put = putrow;
95
96 if (xpos & 0x01)
97 {
98 mask = 0x0f;
99 }
100 else
101 {
102 mask = 0xf0;
103 }
104
105 /* draw line width from left to right */
106 for (column = 0; column < width;)
107 {
108 if ((mask == 0xf0) && (width - column >= 2))
109 {
110 *put++ = pixel;
111 column += 2;
112 }
113 else
114 {
115 /* Set bits first */
116 *put &= (GX_UBYTE)(~mask);
117 *put |= (pixel & mask);
118 mask >>= 4;
119
120 if (mask == 0)
121 {
122 put++;
123 mask = 0xf0;
124 }
125 column++;
126 }
127 }
128
129 /* advance to the next scaneline */
130 putrow += stride;
131 }
132 }
133
134
