我正在参与「兔了个兔」构思投稿大赛，概况请看：「兔了个兔」构思投稿大赛,今年现已来到了兔年，记住去年的时候，看到过不少开发者用Compose画过山君，各式各样的山君都有，那已然现已是兔年了，忽然也想着用Compose来画只兔子试试看，趁便练练手，究竟也好久没碰Compose了
准备工作
兔子主要仍是画在画布上面，所以咱们首要得生成个Canvas，然后确定Canvas的宽高跟画笔色彩
val drawColor = colorResource(id = R.color.color_EC4126)
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
}
宽高这边仅仅写死的两个数值，咱们也能够用体系api来获取真实的屏幕宽高，画笔色彩选用偏红的色彩，究竟要春节了，喜庆点～，接下去开端准备画兔子
脑袋
脑袋其实便是个椭圆，咱们用canvas的drawPath办法去制作，咱们需求做的便是确定这个椭圆的中心点坐标，以及制作这个椭圆的左上坐标以及右下坐标
val startX = screenWidth() / 4
val startY = screenHeight() / 3
val headPath = Path()
headPath.moveTo(screenWidth() / 2, screenHeight() / 2)
headPath.addOval(Rect(startX, startY, screenWidth() - startX, screenHeight() - startY))
headPath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = headPath, color = drawColor, style = Stroke(width = 12f))
}
脑袋的中心点坐标x轴跟y轴别离便是画布宽高的一半，左上的x坐标便是画布宽的四分之一，y坐标便是画布高的三分之一，右下的x坐标便是画布宽减去左上的x坐标，右下的y坐标便是减去左上的y坐标，最终在Canvas里边将这个椭圆的path制作出来，咱们看下作用图
耳朵
画完脑袋咱们接着画耳朵，两只耳朵其实也便是两个椭圆，别离以中心线左右对称，制作思路同画脑袋相同，确定两个path的中心点坐标，以及各自左上跟右下的xy坐标
val leftEarPath = Path()
val leftEarPathX = screenWidth() * 3 / 8
val leftEarPathY = screenHeight() / 6
leftEarPath.moveTo(leftEarPathX, leftEarPathY)
leftEarPath.addOval(
Rect(
leftEarPathX - 60f,
leftEarPathY / 2,
leftEarPathX + 60f,
startY + 30f
)
)
leftEarPath.close()
val rightEarPath = Path()
val rightEarPathX = screenWidth() * 5 / 8
val rightEarPathY = screenHeight() / 6
rightEarPath.moveTo(rightEarPathX, rightEarPathY)
rightEarPath.addOval(
Rect(
rightEarPathX - 60f,
rightEarPathY / 2,
rightEarPathX + 60f,
startY + 30f
)
)
rightEarPath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = leftEarPath, color = drawColor, style = Stroke(width = 10f))
drawPath(path = rightEarPath, color = drawColor, style = Stroke(width = 10f))
}
看下作用图
内耳
这样感觉耳朵不是很立体，看起来有点平面，究竟兔耳朵会有点往里凹的感觉，所以咱们给这副耳朵加个内耳增加点立体感，内耳其实很简单，道理同外面的耳朵相同，仅仅中心点跟左上点，右下点的xy坐标会小一点，咱们略微改一下外耳的path就能够了
val leftEarSubPath = Path()
val leftEarSubPathX = screenWidth() * 3 / 8
val leftEarSubPathY = screenHeight() / 4
leftEarSubPath.moveTo(leftEarSubPathX, leftEarSubPathY)
leftEarSubPath.addOval(
Rect(
leftEarSubPathX - 30f,
screenHeight() / 6,
leftEarSubPathX + 30f,
startY + 30f
)
)
leftEarSubPath.close()
val rightEarSubPath = Path()
val rightEarSubPathX = screenWidth() * 5 / 8
val rightEarSubPathY = screenHeight() / 4
rightEarSubPath.moveTo(rightEarSubPathX, rightEarSubPathY)
rightEarSubPath.addOval(
Rect(
rightEarSubPathX - 30f,
screenHeight() / 6,
rightEarSubPathX + 30f,
startY + 30f
)
)
rightEarSubPath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = leftEarSubPath, color = drawColor, style = Stroke(width = 6f))
drawPath(path = rightEarSubPath, color = drawColor, style = Stroke(width = 6f))
}
看下作用图
有内味儿了，内耳的画笔粗细略微调小了一点，为了突出个近大远小嘛哈哈哈，咱们接着下一步
眼睛
画完耳朵咱们开端画眼睛了，眼睛也很好画，主要是先找到中心点方位就好，中心点的x坐标其实跟耳朵的x坐标是相同的，y坐标在脑袋中心点y坐标略微靠上一点的方位
val leftEyePath = Path()
val leftEyePathX = screenWidth() * 3 / 8
val leftEyePathY = screenHeight() * 11 / 24
leftEyePath.moveTo(leftEyePathX, leftEyePathY)
leftEyePath.addOval(
Rect(
leftEyePathX - 35f,
leftEyePathY - 35f,
leftEyePathX + 35f,
leftEyePathY + 35f
)
)
leftEyePath.close()
val rightEyePath = Path()
val rightEyePathX = screenWidth() * 5 / 8
val rightEyePathY = screenHeight() * 11 / 24
rightEyePath.moveTo(rightEyePathX, rightEyePathY)
rightEyePath.addOval(
Rect(
rightEyePathX - 35f,
rightEyePathY - 35f,
rightEyePathX + 35f,
rightEyePathY + 35f
)
)
rightEyePath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = leftEyePath, color = drawColor, style = Stroke(width = 10f))
drawPath(path = rightEyePath, color = drawColor, style = Stroke(width = 10f))
}
作用图如下
目光有点空洞，无神是不，缺个眼球子，那咱们再给小兔子画上眼球吧，眼球就在眼睛的中心点方位，画一个圆点，圆点就要用到drawCircle，它有这些特色
fun drawCircle(
color: Color,
radius: Float = size.minDimension / 2.0f,
center: Offset = this.center,
/*@FloatRange(from = 0.0, to = 1.0)*/
alpha: Float = 1.0f,
style: DrawStyle = Fill,
colorFilter: ColorFilter? = null,
blendMode: BlendMode = DefaultBlendMode
)
咱们不需求用到全部，只需求用到色彩color，也便是赤色，圆点半径radius，必定要比眼睛的半径要小一点，咱们就设置为10f,圆点中心坐标center,便是眼睛的中心点坐标，知道了今后咱们开端制作眼球
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawCircle(color = drawColor, radius = 10f, center = Offset(leftEyePathX,leftEyePathY))
drawCircle(color = drawColor, radius = 10f, center = Offset(rightEyePathX,rightEyePathY))
}
咱们再看下作用图
鼻子
接下去咱们画鼻子，鼻子必定在脑袋的中心，所以中心点x坐标便是脑袋中心点的x坐标，那鼻子的y坐标就设置成比中心点y坐标略微高一点的方位，代码如下
val nosePath = Path()
val nosePathX = screenWidth() / 2
val nosePathY = screenHeight() * 13 / 24
nosePath.moveTo(nosePathX, nosePathY)
nosePath.addOval(Rect(nosePathX - 15f, nosePathY - 15f, nosePathX + 15f, nosePathY + 15f))
nosePath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = nosePath, color = drawColor, style = Stroke(width = 10f))
}
咱们看下作用图
兔唇
兔子的姿态逐渐出来了，画完鼻子咱们接着画啥呢？没错，兔子最有特色的方位也便是兔唇，咱们脑补下兔唇长啥姿态，首要方位必定是在鼻子的下面，然后从鼻子开端往两头分叉，也便是两个扇形，扇形怎么画呢，咱们也有现成的api，drawArc,咱们看下drawArc都提供了哪些特色
fun drawArc(
color: Color,
startAngle: Float,
sweepAngle: Float,
useCenter: Boolean,
topLeft: Offset = Offset.Zero,
size: Size = this.size.offsetSize(topLeft),
/*@FloatRange(from = 0.0, to = 1.0)*/
alpha: Float = 1.0f,
style: DrawStyle = Fill,
colorFilter: ColorFilter? = null,
blendMode: BlendMode = DefaultBlendMode
)
咱们需求用到的便是色彩color,这个扇形开端视点startAngle,扇形终止的视点sweepAngle,是否扇形两头跟中心点连接起来的布尔值useCenter,扇形的左上方位topLeft以及扇形的巨细size也便是设置半径，知道这些今后咱们开端逐个代入参数吧
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawArc(
color = drawColor,
0f,
120f,
style = Stroke(width = 10f),
useCenter = false,
size = Size(120f, 120f),
topLeft = Offset(nosePathX - 120f, nosePathY)
)
drawArc(
color = drawColor,
180f,
-120f,
style = Stroke(width = 10f),
useCenter = false,
size = Size(120f, 120f),
topLeft = Offset(nosePathX + 10f, nosePathY)
)
}
画兔唇的时候其实便是在鼻子的两头各画一个坐标轴，左边的兔唇开端视点便是从x轴开端也便是0度，顺时针旋转120度，左上方位的x坐标刚好离开鼻子一个半径的方位，右边的兔唇刚好相反，逆时针旋转120度，开端视点是180度，左上方位的x坐标刚好在鼻子的方位那里，略微加个10f让兔唇能够对称一些，咱们看下作用图
胡须
脸上如同空了点，兔子的胡须还没有呢，胡须其实便是两头各画三条线，用drawLine这个api,开端方位的x坐标跟眼睛中心点的x坐标相同，中心胡须开端方位的y坐标跟鼻子的y坐标相同，上下胡须的y坐标各减去一定的数值
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawLine(
color = drawColor,
start = Offset(leftEyePathX, nosePathY - 60f),
end = Offset(leftEyePathX - 250f, nosePathY - 90f),
strokeWidth = 5f,
cap = StrokeCap.Round
)
drawLine(
color = drawColor,
start = Offset(leftEyePathX, nosePathY),
end = Offset(leftEyePathX - 250f, nosePathY),
strokeWidth = 5f,
cap = StrokeCap.Round
)
drawLine(
color = drawColor,
start = Offset(leftEyePathX, nosePathY + 60f),
end = Offset(leftEyePathX - 250f, nosePathY + 90f),
strokeWidth = 5f,
cap = StrokeCap.Round
)
drawLine(
color = drawColor,
start = Offset(rightEyePathX, nosePathY - 60f),
end = Offset(rightEyePathX + 250f, nosePathY - 90f),
strokeWidth = 5f,
cap = StrokeCap.Round
)
drawLine(
color = drawColor,
start = Offset(rightEyePathX, nosePathY),
end = Offset(rightEyePathX + 250f, nosePathY),
strokeWidth = 5f,
cap = StrokeCap.Round
)
drawLine(
color = drawColor,
start = Offset(rightEyePathX, nosePathY + 60f),
end = Offset(rightEyePathX + 250f, nosePathY + 90f),
strokeWidth = 5f,
cap = StrokeCap.Round
)
}
很简单的画了六条线，线的粗细也略微设置的小一点，究竟胡须仍是比较细的，咱们看下作用图
就这样兔子脑袋部分所有元素都画完了，咱们接着给兔子画身体
身体
身体其实也是个椭圆，方位刚好在画布下方三分之一的方位，左上x坐标比脑袋左上x坐标大一点，y坐标便是画布三分之二的方位处，右下x坐标比脑袋右下x坐标略微小一点，y坐标便是画布的底端，知道今后咱们就仿照着脑袋画身体
val bodyPath = Path()
val bodyPathX = screenWidth() / 2
val bodyPathY = screenHeight() * 5 / 6
bodyPath.moveTo(bodyPathX, bodyPathY)
bodyPath.addOval(
Rect(
startX + 50f,
screenHeight() * 2 / 3,
screenWidth() - startX - 50f,
screenHeight()
)
)
bodyPath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = bodyPath, color = drawColor, style = Stroke(width = 10f))
}
作用图如下
双爪
画完身体咱们再画兔子的双爪，双爪其实也是画两个椭圆，椭圆中心点的x坐标同两只眼睛的x坐标相同，y坐标在画布六分之五的方位
val leftHandPath = Path()
val leftHandPathX = screenWidth() * 3 / 8
val leftHandPathY = screenHeight() * 5 / 6
leftHandPath.moveTo(leftHandPathX, leftHandPathY)
leftHandPath.addOval(
Rect(
leftHandPathX - 35f,
leftHandPathY - 90f,
leftHandPathX + 35f,
leftHandPathY + 90f
)
)
leftHandPath.close()
val rightHandPath = Path()
val rightHandPathX = screenWidth() * 5 / 8
val rightHandPathY = screenHeight() * 5 / 6
rightHandPath.moveTo(rightHandPathX, rightHandPathY)
rightHandPath.addOval(
Rect(
rightHandPathX - 35f,
rightHandPathY - 90f,
rightHandPathX + 35f,
rightHandPathY + 90f
)
)
rightHandPath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = leftHandPath, color = drawColor, style = Stroke(width = 10f))
drawPath(path = rightHandPath, color = drawColor, style = Stroke(width = 10f))
}
咱们看下作用图
尾巴
还差最终一步，咱们给兔子画上尾巴，尾巴的中心点x坐标便是画布宽度减去脑袋右边x轴坐标，尾巴中心点的y坐标便是画布高度减去一定的数值，咱们看下代码
val tailPath = Path()
val tailPathX = screenWidth() - startX
val tailPathY = screenHeight() - 200f
tailPath.moveTo(tailPathX, tailPathY)
tailPath.addOval(Rect(tailPathX - 60f, tailPathY - 90f, tailPathX + 60f, tailPathY + 90f))
tailPath.close()
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawPath(path = tailPath, color = drawColor, style = Stroke(width = 10f))
}
就这样一只兔子画完了，咱们看下最终作用图
看起来像那么回事了，咱们再略微点缀下，布景咱们发现还有点单调，究竟是春节了嘛，尽管多地不让放焰火，但咱们看看仍是能够的，网上找张焰火图片给兔子当布景吧，刚好也有drawImage这样的api能够将图片制作到画布上，代码如下
val bgBitmap = ImageBitmap.imageResource(id = R.drawable.firework_night)
Canvas(
modifier = Modifier
.size(screenWidth().dp, screenHeight().dp)
.background(color = Color.White)
) {
drawImage(image = bgBitmap,
srcOffset = IntOffset(0,0),
srcSize = IntSize(bgBitmap.width,bgBitmap.height),
dstSize = IntSize(screenWidth().toInt()*5/4,screenHeight().toInt()*5/4),
dstOffset = IntOffset(0,0)
)
}
咱们来看下作用怎么样
嗯～～功德圆满～～如同也不是很好看哈哈哈，不过重点咱也不是为了美观，而是一个春节了图个涵义，另一个便是用下Compose里边Canvas这些api，究竟跟着kotlin逐渐成熟，个人感觉Compose很有或许成为Android今后干流的UI开发形式
最终给我们拜个早年了，祝我们兔年大吉，“兔”飞猛进～～
