1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8#include "SkStackViewLayout.h"
9
10SkStackViewLayout::SkStackViewLayout()
11{
12    fMargin.set(0, 0, 0, 0);
13    fSpacer    = 0;
14    fOrient    = kHorizontal_Orient;
15    fPack    = kStart_Pack;
16    fAlign    = kStart_Align;
17    fRound    = false;
18}
19
20void SkStackViewLayout::setOrient(Orient ori)
21{
22    SkASSERT((unsigned)ori < kOrientCount);
23    fOrient = SkToU8(ori);
24}
25
26void SkStackViewLayout::getMargin(SkRect* margin) const
27{
28    if (margin)
29        *margin = fMargin;
30}
31
32void SkStackViewLayout::setMargin(const SkRect& margin)
33{
34    fMargin = margin;
35}
36
37void SkStackViewLayout::setSpacer(SkScalar spacer)
38{
39    fSpacer = spacer;
40}
41
42void SkStackViewLayout::setPack(Pack pack)
43{
44    SkASSERT((unsigned)pack < kPackCount);
45    fPack = SkToU8(pack);
46}
47
48void SkStackViewLayout::setAlign(Align align)
49{
50    SkASSERT((unsigned)align < kAlignCount);
51    fAlign = SkToU8(align);
52}
53
54void SkStackViewLayout::setRound(bool r)
55{
56    fRound = SkToU8(r);
57}
58
59////////////////////////////////////////////////////////////////////////////////
60
61typedef SkScalar (*AlignProc)(SkScalar childLimit, SkScalar parentLimit);
62typedef SkScalar (SkView::*GetSizeProc)() const;
63typedef void (SkView::*SetLocProc)(SkScalar coord);
64typedef void (SkView::*SetSizeProc)(SkScalar coord);
65
66static SkScalar left_align_proc(SkScalar childLimit, SkScalar parentLimit) { return 0; }
67static SkScalar center_align_proc(SkScalar childLimit, SkScalar parentLimit) { return SkScalarHalf(parentLimit - childLimit); }
68static SkScalar right_align_proc(SkScalar childLimit, SkScalar parentLimit) { return parentLimit - childLimit; }
69static SkScalar fill_align_proc(SkScalar childLimit, SkScalar parentLimit) { return 0; }
70
71/*    Measure the main-dimension for all the children. If a child is marked flex in that direction
72    ignore its current value but increment the counter for flexChildren
73*/
74static SkScalar compute_children_limit(SkView* parent, GetSizeProc sizeProc, int* count,
75                                       uint32_t flexMask, int* flexCount)
76{
77    SkView::B2FIter    iter(parent);
78    SkView*            child;
79    SkScalar        limit = 0;
80    int                n = 0, flex = 0;
81
82    while ((child = iter.next()) != NULL)
83    {
84        n += 1;
85        if (child->getFlags() & flexMask)
86            flex += 1;
87        else
88            limit += (child->*sizeProc)();
89    }
90    if (count)
91        *count = n;
92    if (flexCount)
93        *flexCount = flex;
94    return limit;
95}
96
97void SkStackViewLayout::onLayoutChildren(SkView* parent)
98{
99    static AlignProc gAlignProcs[] = {
100        left_align_proc,
101        center_align_proc,
102        right_align_proc,
103        fill_align_proc
104    };
105
106    SkScalar            startM, endM, crossStartM, crossLimit;
107    GetSizeProc            mainGetSizeP, crossGetSizeP;
108    SetLocProc            mainLocP, crossLocP;
109    SetSizeProc            mainSetSizeP, crossSetSizeP;
110    SkView::Flag_Mask    flexMask;
111
112    if (fOrient == kHorizontal_Orient)
113    {
114        startM        = fMargin.fLeft;
115        endM        = fMargin.fRight;
116        crossStartM    = fMargin.fTop;
117        crossLimit    = -fMargin.fTop - fMargin.fBottom;
118
119        mainGetSizeP    = &SkView::width;
120        crossGetSizeP    = &SkView::height;
121        mainLocP    = &SkView::setLocX;
122        crossLocP    = &SkView::setLocY;
123
124        mainSetSizeP  = &SkView::setWidth;
125        crossSetSizeP = &SkView::setHeight;
126
127        flexMask    = SkView::kFlexH_Mask;
128    }
129    else
130    {
131        startM        = fMargin.fTop;
132        endM        = fMargin.fBottom;
133        crossStartM    = fMargin.fLeft;
134        crossLimit    = -fMargin.fLeft - fMargin.fRight;
135
136        mainGetSizeP    = &SkView::height;
137        crossGetSizeP    = &SkView::width;
138        mainLocP    = &SkView::setLocY;
139        crossLocP    = &SkView::setLocX;
140
141        mainSetSizeP  = &SkView::setHeight;
142        crossSetSizeP = &SkView::setWidth;
143
144        flexMask    = SkView::kFlexV_Mask;
145    }
146    crossLimit += (parent->*crossGetSizeP)();
147    if (fAlign != kStretch_Align)
148        crossSetSizeP = NULL;
149
150    int            childCount, flexCount;
151    SkScalar    childLimit = compute_children_limit(parent, mainGetSizeP, &childCount, flexMask, &flexCount);
152
153    if (childCount == 0)
154        return;
155
156    childLimit += (childCount - 1) * fSpacer;
157
158    SkScalar        parentLimit = (parent->*mainGetSizeP)() - startM - endM;
159    SkScalar        pos = startM + gAlignProcs[fPack](childLimit, parentLimit);
160    SkScalar        flexAmount = 0;
161    SkView::B2FIter    iter(parent);
162    SkView*            child;
163
164    if (flexCount > 0 && parentLimit > childLimit)
165        flexAmount = (parentLimit - childLimit) / flexCount;
166
167    while ((child = iter.next()) != NULL)
168    {
169        if (fRound)
170            pos = SkScalarRoundToScalar(pos);
171        (child->*mainLocP)(pos);
172        SkScalar crossLoc = crossStartM + gAlignProcs[fAlign]((child->*crossGetSizeP)(), crossLimit);
173        if (fRound)
174            crossLoc = SkScalarRoundToScalar(crossLoc);
175        (child->*crossLocP)(crossLoc);
176
177        if (crossSetSizeP)
178            (child->*crossSetSizeP)(crossLimit);
179        if (child->getFlags() & flexMask)
180            (child->*mainSetSizeP)(flexAmount);
181        pos += (child->*mainGetSizeP)() + fSpacer;
182    }
183}
184
185//////////////////////////////////////////////////////////////////////////////////////
186
187#ifdef SK_DEBUG
188    static void assert_no_attr(const SkDOM& dom, const SkDOM::Node* node, const char attr[])
189    {
190        const char* value = dom.findAttr(node, attr);
191        if (value)
192            SkDebugf("unknown attribute %s=\"%s\"\n", attr, value);
193    }
194#else
195    #define assert_no_attr(dom, node, attr)
196#endif
197
198void SkStackViewLayout::onInflate(const SkDOM& dom, const SkDOM::Node* node)
199{
200    int            index;
201    SkScalar    value[4];
202
203    if ((index = dom.findList(node, "orient", "horizontal,vertical")) >= 0)
204        this->setOrient((Orient)index);
205    else {
206        assert_no_attr(dom, node, "orient");
207        }
208
209    if (dom.findScalars(node, "margin", value, 4))
210    {
211        SkRect    margin;
212        margin.set(value[0], value[1], value[2], value[3]);
213        this->setMargin(margin);
214    }
215    else {
216        assert_no_attr(dom, node, "margin");
217        }
218
219    if (dom.findScalar(node, "spacer", value))
220        this->setSpacer(value[0]);
221    else {
222        assert_no_attr(dom, node, "spacer");
223        }
224
225    if ((index = dom.findList(node, "pack", "start,center,end")) >= 0)
226        this->setPack((Pack)index);
227    else {
228        assert_no_attr(dom, node, "pack");
229        }
230
231    if ((index = dom.findList(node, "align", "start,center,end,stretch")) >= 0)
232        this->setAlign((Align)index);
233    else {
234        assert_no_attr(dom, node, "align");
235        }
236}
237
238///////////////////////////////////////////////////////////////////////////////////////////
239
240SkFillViewLayout::SkFillViewLayout()
241{
242    fMargin.setEmpty();
243}
244
245void SkFillViewLayout::getMargin(SkRect* r) const
246{
247    if (r)
248        *r = fMargin;
249}
250
251void SkFillViewLayout::setMargin(const SkRect& margin)
252{
253    fMargin = margin;
254}
255
256void SkFillViewLayout::onLayoutChildren(SkView* parent)
257{
258    SkView::B2FIter    iter(parent);
259    SkView*            child;
260
261    while ((child = iter.next()) != NULL)
262    {
263        child->setLoc(fMargin.fLeft, fMargin.fTop);
264        child->setSize(    parent->width() - fMargin.fRight - fMargin.fLeft,
265                        parent->height() - fMargin.fBottom - fMargin.fTop);
266    }
267}
268
269void SkFillViewLayout::onInflate(const SkDOM& dom, const SkDOM::Node* node)
270{
271    this->INHERITED::onInflate(dom, node);
272    (void)dom.findScalars(node, "margin", (SkScalar*)&fMargin, 4);
273}
274