1// Copyright (C) 2023 The Qt Company Ltd.
2// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
3
4#include "qsggradientcache_p.h"
5
6#include <QtGui/private/qdrawhelper_p.h>
7#include <QtGui/rhi/qrhi.h>
8
9#include <QtQuick/qsgtexture.h>
10#include <QtQuick/private/qsgplaintexture_p.h>
11
12QT_BEGIN_NAMESPACE
13
14static void generateGradientColorTable(const QSGGradientCacheKey &gradient,
15 uint *colorTable, int size, float opacity)
16{
17 int pos = 0;
18 const QGradientStops &s = gradient.stops;
19 Q_ASSERT(!s.isEmpty());
20 const bool colorInterpolation = true;
21
22 uint alpha = qRound(f: opacity * 256);
23 uint current_color = ARGB_COMBINE_ALPHA(s[0].second.rgba(), alpha);
24 qreal incr = 1.0 / qreal(size);
25 qreal fpos = 1.5 * incr;
26 colorTable[pos++] = ARGB2RGBA(x: qPremultiply(x: current_color));
27
28 while (fpos <= s.first().first) {
29 colorTable[pos] = colorTable[pos - 1];
30 pos++;
31 fpos += incr;
32 }
33
34 if (colorInterpolation)
35 current_color = qPremultiply(x: current_color);
36
37 const int sLast = s.size() - 1;
38 for (int i = 0; i < sLast; ++i) {
39 qreal delta = 1/(s[i+1].first - s[i].first);
40 uint next_color = ARGB_COMBINE_ALPHA(s[i + 1].second.rgba(), alpha);
41 if (colorInterpolation)
42 next_color = qPremultiply(x: next_color);
43
44 while (fpos < s[i+1].first && pos < size) {
45 int dist = int(256 * ((fpos - s[i].first) * delta));
46 int idist = 256 - dist;
47 if (colorInterpolation)
48 colorTable[pos] = ARGB2RGBA(x: INTERPOLATE_PIXEL_256(x: current_color, a: idist, y: next_color, b: dist));
49 else
50 colorTable[pos] = ARGB2RGBA(x: qPremultiply(x: INTERPOLATE_PIXEL_256(x: current_color, a: idist, y: next_color, b: dist)));
51 ++pos;
52 fpos += incr;
53 }
54 current_color = next_color;
55 }
56
57 uint last_color = ARGB2RGBA(x: qPremultiply(ARGB_COMBINE_ALPHA(s[sLast].second.rgba(), alpha)));
58 for ( ; pos < size; ++pos)
59 colorTable[pos] = last_color;
60
61 colorTable[size-1] = last_color;
62}
63
64QSGGradientCache::~QSGGradientCache()
65{
66 qDeleteAll(c: m_textures);
67}
68
69QSGGradientCache *QSGGradientCache::cacheForRhi(QRhi *rhi)
70{
71 static QHash<QRhi *, QSGGradientCache *> caches;
72 auto it = caches.constFind(key: rhi);
73 if (it != caches.constEnd())
74 return *it;
75
76 QSGGradientCache *cache = new QSGGradientCache;
77 rhi->addCleanupCallback(callback: [cache](QRhi *rhi) {
78 caches.remove(key: rhi);
79 delete cache;
80 });
81 caches.insert(key: rhi, value: cache);
82 return cache;
83}
84
85QSGTexture *QSGGradientCache::get(const QSGGradientCacheKey &grad)
86{
87 QSGPlainTexture *tx = m_textures[grad];
88 if (!tx) {
89 static const int W = 1024; // texture size is 1024x1
90 QImage gradTab(W, 1, QImage::Format_RGBA8888_Premultiplied);
91 if (!grad.stops.isEmpty())
92 generateGradientColorTable(gradient: grad, colorTable: reinterpret_cast<uint *>(gradTab.bits()), size: W, opacity: 1.0f);
93 else
94 gradTab.fill(color: Qt::black);
95 tx = new QSGPlainTexture;
96 tx->setImage(gradTab);
97 switch (grad.spread) {
98 case QGradient::PadSpread:
99 tx->setHorizontalWrapMode(QSGTexture::ClampToEdge);
100 tx->setVerticalWrapMode(QSGTexture::ClampToEdge);
101 break;
102 case QGradient::RepeatSpread:
103 tx->setHorizontalWrapMode(QSGTexture::Repeat);
104 tx->setVerticalWrapMode(QSGTexture::Repeat);
105 break;
106 case QGradient::ReflectSpread:
107 tx->setHorizontalWrapMode(QSGTexture::MirroredRepeat);
108 tx->setVerticalWrapMode(QSGTexture::MirroredRepeat);
109 break;
110 default:
111 qWarning(msg: "Unknown gradient spread mode %d", grad.spread);
112 break;
113 }
114 tx->setFiltering(QSGTexture::Linear);
115 m_textures[grad] = tx;
116 }
117 return tx;
118}
119
120
121QT_END_NAMESPACE
122

source code of qtdeclarative/src/quick/scenegraph/util/qsggradientcache.cpp